Building Integrated Photovoltaic Research Articles

Building Integrated Photovoltaics (BIPV): Analysis of the Technological Transfer Process and Innovation Dynamics in the Swiss Building Sector

Solar has confirmed its dominance among all power generation technologies, and along with the demand for zero-emission buildings, Photovoltaics (PV) is contributing to transforming the building skin. More than 200 products for Building Integrated Photovoltaics (BIPV) are commercialized nowadays in the EU market. However, only 1–3% of all PV installations are BIPV due to the weak penetration in the construction sector. At the state of the art, the sector lacks a specific analysis from a construction technology perspective, describing the dynamics and the traits that BIPV innovation articulates on construction and architectural processes. The authors, elaborating a new model from the building technology sector to explore the relationship between PV technology and architectural innovation, aim to identify the main principles, forms, and approaches that describe the structural organization of the “integrability” concept of PV in buildings. This study applies the method to a database of 233 real buildings located in Switzerland, a unique country leading with a 10% BIPV rate on PV installations documented between the years 1997 and 2023. The novel findings of the research suggest the definition of the levels of innovation and the reference traits of the innovative process of BIPV in the Swiss construction sector, which can also be used in other practical applications and contexts. The results of the paper are expected to impact both the scientific academy and the key players from the construction sector, encouraging the adoption of an integrated research and design approach to revolutionize the energy role of building skins with PV.

Experimental investigation of photoelectrical performance and thermal characteristics of ventilated building-integrated photovoltaic system utilizing lightweight and flexible crystalline silicon module

The existing large-scale of industrial buildings with lightweight insulated roofing structures presents a challenge for traditional glass crystalline silicon photovoltaic (PV) systems due to insufficient load-bearing capacity. Meanwhile, traditional PV rooftop applications also face challenges due to limited rooftop resources. To address these issues, this study proposes a ventilated building-integrated lightweight photovoltaic (VL-BIPV) system. The VL-BIPV system incorporates lightweight and flexible crystalline silicon modules, which increase rooftop load by about 6 kg/m2. Additionally, the system features a ventilation channel design to enhance thermal management performance. To evaluate the PV performance and thermal characteristics of the proposed system, an experimental setup was implemented to compare the performances of the VL-BIPV system with a building-attached lightweight photovoltaic (L-BAPV) system that utilizes color steel sheet base plates. The results demonstrate the exceptional performance of VL-BIPV system, with a 100.56% higher ratio of the product of short-circuit current and open-circuit voltage compared to L-BAPV. Moreover, the VL-BIPV system achieved a 1.77% increase in PV efficiency and a 2.35% enhancement in daily electricity generation. In hot weather, the adoption of VL-BIPV reduced the extreme temperature of PV cells by 9.23 °C below 85 °C, surpassing the 6.29 °C reduction achieved by L-BAPV system. Furthermore, the ventilation channel exhibited a gradual temperature increase with slower changes in the flow direction, while the base plate temperature decreased by 13.41 °C, which indicates that VL-BIPV can effectively reduce solar heat gain in the building envelope and improve the indoor thermal environment. The research findings provide important guidance for promoting and applying VL-BIPV technology in large-scale industrial buildings with low rooftop load-bearing capacity, thereby promoting the production and utilization of clean electricity in industrial parks.

Performance improvement of building-integrated photovoltaic panels using a composite phase change material-carbon foam heat sink: An experimental study

Building-integrated photovoltaic (BIPV) panels are important for enhancing building self-power generation, promoting sustainable energy practices, and reducing dependence on the grid. Nevertheless, the efficiency and output power of these panels are negatively affected by the temperature increase caused by incident solar radiation. Thus, the present study introduces an innovative paraffin/carbon foam composite phase change material for efficient thermal management of building-integrated photovoltaic panels. Through indoor and outdoor experimental tests, the study evaluated and compared the performance of the proposed system. This system integrates a PV panel with an RT-55 phase change material and carbon foam structure (BIPV-PCM-CF) and was compared to three other cases, including a naturally cooled free PV panel, a building wall integrated PV panel to simulate conventional building-integrated photovoltaic system (BIPV), and a PV panel integrated with only RT-55 paraffin wax as the phase change material (BIPV-PCM). The study found that integrating the PV cell into building walls (BIVP) increased its temperature by 9.61 °C and decreased generated power and efficiency by 5.11 % and 10.95 %, respectively, compared to the free PV panel. On the other hand, the BIPV-PCM panel reduced module temperature by 18.1 °C but could not solidify the needed amount of PCM during the nighttime. The BIPV-PCM-CF panel, which incorporated carbon foam with PCM, outperformed the other systems, producing a cooling performance of 22.94 °C and increasing electricity generation and system efficiency by an average of 12.64 % and 27.35 %, respectively, compared to the free PV panel. These findings highlight effective strategies to promote sustainable energy practices, improve the electric performance of BIPV panels, and reduce dependence on non-renewable energy sources in buildings.

Energy-saving strategies to convert existing campus to smart campus: a conservative method analysis

Energy consumption has wide applications in the construction industry. The pattern of energy demand depends on the nature of energy usage in accordance with time. Prominence is given to meet the demand without forfeiture of energy. This paper focuses on the importance of developing a smart campus and energy management. In the present study, a prominent engineering institute located in Karnataka, India, is considered for analysis. The approaches considered here are installing solar roof panels and replacing existing electrical fixtures with light-emitting diode (LED) fixtures. The cost and energy consumption analysis before and after the application of these methods will give a strong image of how energy and money can be saved and are useful for society. The initial investment may slightly be high but the payback period is quite early. Results of the study indicate that the initial investment required for solar panel installation and replacement of existing electrical fixtures with LED fixtures for interiors and corridors at the institution has proved worthwhile by various investment criteria used in the project. The study implicates a positive step towards energy-saving strategies, a revolutionary change in the energy sector and the development of the country.

Assessment of evaporative porous clay cooler for Building-Integrated photovoltaic systems via energy, exergy, economic and environmental approaches

A thorough study has been conducted for the energy, exergy, economic and environmental analysis to investigate the feasibility of utilizing an evaporative porous structure cooler for the building-integrated photovoltaic (BIPV) system at different building’s sides and directions. Photovoltaic panels within the BIPV systems dissipate their heat to the building’s sides which contribute to rise the interior building’s temperature. In the proposed system, a water-saturated evaporative porous clay cooler is being installed on the back surface of the PV panels to absorb and dissipate their heat by latent evaporation through an evaporation cooling process. A transient numerical heat and mass transfer model based on energy, exergy, economic and environmental approaches was proposed to assist the feasibility of cooling BIPV system via evaporative porous structure cooler. The model was also validated experimentally in the present study. The results exhibited that, comparing with conventional BIPV systems, the presented BIPV/Clay cooling system achieved a peak photovoltaic temperature reduction of 19.1 °C, with a maximum enhancement in the photovoltaic system’s electrical efficiency, electrical power, and exergy efficiency of 9.8 %, 12.6 % and 11.8 %, respectively. The ultimate reduction in the building’s annual thermal load was around 53.8 % when the clay evaporative cooling approach is applied, while the cost of electricity production reduced ultimately by 7.9 %, (from 0.151 $/kWh to 0.134 $/kWh). Further, the payback period decreased by 2.33 years and the annual amount of CO2 emissions decreased by 10.4 % for the utilized BIPV/Clay cooling system compared with the conventional BIPV system.

Performance enhancement of porous clay cooler for BIPV applications using hollowed clay structures and metallic extended fins as evaporation and thermal conductivity enhancers

This paper investigates the employing of a passive evaporative cooling approach to mitigate the temperature rise of PV panels within building-integrated photovoltaic (BIPV) systems. The investigation explores enhancing the heat transfer capabilities of composite clay layers by incorporating thermal conductive materials such as iron-oxide and zinc-oxide. This enhancement aimed to improve the overall thermal properties of the composite clay structures, thereby boosting heat transfer rates. Additionally, two distinct designs were evaluated as well: one integrating hollowed clay layer and the other featuring a clay layer with extended fins to enhance both heat and mass transfer rates within the evaporative porous clay structure. A series of experiments conducted under real conditions using prototyped building rooms to simulate real BIPV systems to assess the cooling performance of the presented scenarios. The results revealed that the hollowed clay layer achieved the most substantial decrease in PV panel temperature, with a reduction of 16.5 % compared to the findings with a solid clay layer. In contrast, the composite Iron-oxide/clay layer demonstrated the smallest decrease in PV temperature at 11 %. Moreover, utilizing the hollowed clay structure led to a 6.3 % increase in average PV output power, as well as around 4.5 % enhancement in average photovoltaic’s efficiency compared to the outcomes observed with the solid clay layer. Moreover, incorporating the hollowed clay layer resulted in the most significant decrease in the building's annual load, achieving a reduction of 79.6 %. This signifies approximately a 2 % higher enhancement in cooling capabilities compared to utilizing solid clay layer. Further, the cost of electricity production decreased by 7.7 % (from 0.104 $/kWh to 0.096 $/kWh) following the incorporation of the hollowed clay layer, while the payback time was reduced by roughly 0.8 years compared to utilizing the solid clay layer and by 1.7 years in comparison to the non-cooled BIPV system.

Optimal sizing of off-grid microgrid Building-Integrated-Photovoltaic system with battery for a Net Zero Energy Residential Building in different climates of Morocco

An optimal sizing of an off-grid microgrid system composed of photovoltaic (PV)/building integrated photovoltaic (BIPV)/battery energy storage installation is undergone for Net Zero Energy Residential Building blocks across six different climates of Morocco in order to reach the objective of providing all energy load requirements at the minimum. The Particle Swarm Optimization algorithm is used to find the optimal sizing of the system, by considering the hourly spatiotemporal variations in both solar energy availability and energy demand variation, with the lowest Total Annualized Cost as the objective function and capacities of BIPV and battery as decision variables. The methodology adopted focuses on main load fulfillment through direct PV and BIPV power supply, backed by battery energy storage technology, to continually guarantee self-sufficiency. A key metric, the load cover factor, is introduced to quantify the ratio by which the load demand is satisfied by the solar PV and BIPV systems. The findings show that the optimal sizing of the BIPV system can help to improve the load cover factor by 0.68-2.58%. Moreover, integrating BIPV system to PV system and Battery leads to a reduction in the Levelized Cost of Energy with approximately 8.7-20.72 %, as opposed to utilizing only the PV system and battery. Depending on the local climate, the levelized cost of energy ranges from 0.366 $/kWh in Ouarzazate city up to 0.664 $/kWh.in Ifrane city. Lastly, this holistic approach aims to transform the building from its traditional role as an energy consumer to a carbon-free electricity generator.

Colouring solutions for building integrated photovoltaic modules: A review

As global decarbonisation requires the widespread adoption of solar photovoltaic (PV) electricity, addressing challenges related to land use has become relevant. The conflict between PV installations and other land uses, such as forestry or agriculture, highlights the urgency for alternative solutions. Integrating PV technology into the built environment is a compelling strategy to mitigate these challenges, enabling electricity generation precisely where it is needed. In the context of buildings integrated photovoltaics (BIPV), PV modules serve a dual purpose, functioning both as electricity generators and integral components of the architectural design. Therefore, the architecture requirements — specifically in terms of shape, size, and colour— become relevant for BIPV modules. This paper offers a general overview of the diverse colouring technologies employed for BIPV modules, describing their functioning, challenges, and advantages. An examination of the current landscape of coloured PV products involving considerations of pricing and power output is presented. Additionally, this work addresses the critical topics of reliability and stability in colour solutions, outlining methodologies for quantitative colour characterization. It provides foresight into the potential challenges facing installations in the future and explores the multifaceted social, economic, and environmental implications of this evolving technology.

Building energy saving of a rotatable radiative cooling-photovoltaic system by alternate utilization of solar energy and radiative cooling

Building-integrated photovoltaic (BIPV) and Building-integrated radiative cooling (BIRC) are recognized as efficient renewable utilization technologies that can promote building energy savings and reduce carbon dioxide emissions. An innovative rotatable radiative cooling-photovoltaic (RRC-PV) system is proposed, which has multi-functions of photovoltaic power generation, radiative cooling power utilization, and overhang shading. The nonstop alternate utilization of solar energy and free cooling energy from the outer space can be realized. The system breaks the constraint of limited building surface areas and has significant meaning for the renewable energy exploit in high-density cities.In this study, the model of the RRC-PV module is developed and validated with experimental data. Rhino and Grasshopper platform are used, and the radiative cooling power is calculated with a self-developed GH_Cpython program. The RRC-PV system is applied to a typical office in Shenzhen with hot summer and warm winter climate. By applying the RRC-PV modules with total area of 1.68 m2, the daytime PV power generation is 361.9 kWh throughout the year, and the nocturnal radiative cooling power utilization is 246.9 kWh. The building energy usage intensity was reduced from 89.7 kWh/(year·m2) to 83.7 kWh/(year·m2), resulting in payback period of less than 6 years.

Semitransparent organic photovoltaics enabled by transparent p-type inorganic semiconductor and near-infrared acceptor

Semitransparent organic photovoltaics (STOPVs) have gained wide attention owing to their promising applications in building-integrated photovoltaics, agrivoltaics, and floating photovoltaics. Organic semiconductors with high charge carrier mobility usually have planar and conjugated structures, thereby showing strong absorption in visible region. In this work, a new concept of incorporating transparent inorganic semiconductors is proposed for high-performance STOPVs. Copper(I) thiocyanate (CuSCN) is a visible-transparent inorganic semiconductor with an ionization potential of 5.45 eV and high hole mobility. The transparency of CuSCN benefits high average visible transmittance (AVT) of STOPVs. The energy levels of CuSCN as donor match those of near-infrared small molecule acceptor BTP-eC9, and the formed heterojunction exhibits an ability of exciton dissociation. High mobility of CuSCN contributes to a more favorable charge transport channel and suppresses charge recombination. The control STOPVs based on PM6/BTP-eC9 exhibit an AVT of 19.0% with a power conversion efficiency (PCE) of 12.7%. Partial replacement of PM6 with CuSCN leads to a 63% increase in transmittance, resulting in a higher AVT of 30.9% and a comparable PCE of 10.8%.

Fire Dynamics and Evacuation Simulation Study on the Library Adapting BIPV Based on the Experimental Data of a Cone Calorimeter

A building integrated photovoltaic (BIPV) system can function as a solar cell and as a building exterior material. As some of its components are made of combustible materials, it is necessary to evaluate the risk of fire. In this study, the risk of fire before and after BIPV installation was compared through fire simulation using the PyroSim program. Prior to the simulation, a BIPV combustion characteristic database was established via a cone calorimeter experiment with a BIPV system panel, and the results were analyzed through a fire simulation using these experimental values as input values. The fire risk evaluation confirmed that when BIPV was installed, the fire propagation due to vertical diffusion was fast. Additionally, the amount of heat and smoke emitted increased, resulting in an increase in the risk of fire by 54.94% based on the center of the building at 805 s. Therefore, it is expected that the results of this study will contribute to securing the reliability of evacuation and manual measures for people in BIPV-installed buildings as well as improve fire safety.

Unveiling the potential of perovskite solar systems in building integrated installations: A consequential and prospective life cycle assessment and economic analysis

This paper addresses an integrated economic and environmental assessment where a consequential and prospective life cycle approach is applied to perovskite (PSK) building integrated photovoltaic (BIPV) systems. Two configurations are considered: slanted roof (r-BIPV) installations, and the fenestration of façades (f-BIPV). Concerning r-BIPV, PSK systems are expected to compete with crystalline silicon (c-Si) modules; whereas a glass façade is chosen as an alternative reference for f-BIPV. Assuming economic rationality as the main criteria for the adoption of technologies, a deployment time for the PSK system is estimated and the economic and environmental advantages in the Italian context are evaluated. This assessment is based on three foreground scenarios addressing the gradual development of PSK systems. The results show that while c-Si modules are preferred in the market of r-BIPV systems, PSK modules will find space in f-BIPV applications. Depending on the selected scenario, the economic benefits accumulated by Italian energy users are assessed between −0.5 % and −10.3 %. On the other hand, PSK systems imply a variation of the national GHGs emissions that ranges between + 0.01 % and −7.5 %. Depending on the scenario, the PSK-based f-BIPV systems can provide either environmental benefits (i.e., cumulative energy demand) or burdens (i.e., ecotoxicity indicators).

Energy consumption, power generation and performance analysis of solar photovoltaic module based building roof

Building energy intensity (BEI) of typical office buildings in Malaysia ranges from 200 to 250 kWh/m2/year, wherein a substantial portion is due to the cooling system. This study evaluates of the performance and suitability of double-laminated monocrystalline solar photovoltaic (PV) glass in comparison to traditional solar PV systems installed on roofs in Malaysian conditions. To address this aim, simulation studies have been conducted to examine the efficacy of Building Attached Photovoltaic (BAPV) and Building Integrated Photovoltaic (BIPV) systems. Key parameters such as heat transfer across the building envelope, cooling demand, daylight utilization, and solar irradiance were analyzed. Additionally, an evaluation of economic viability, including Return on Investment (ROI) and payback period (PBP), was undertaken. Analysis showed that more heat was transferred through the roof on the BIPV building as the U-value of the solar PV glass was higher than the metal deck roof on the BAPV building. The lighting energy in the BIPV building can be saved by up to 80 % as sufficient daylight was entering the building. More than 30 % of the building area had a daylight factor of 1.0 %–3.5 %. From economic viewpoint, the double-laminated monocrystalline solar PV glass had a longer payback period as the initial capital cost was much higher even though the one-off savings and annual savings in the BIPV building were more than the BAPV building.

Resilience-Oriented Planning of Urban Distribution System Source–Network–Load–Storage in the Context of High-Penetrated Building-Integrated Resources

Building-integrated flexible resources can offer economical availability to accommodate high-penetrated renewable energy sources (RESs), which can be potentially coordinated to achieve cost-effective supply. This paper proposes a resilience-oriented planning model of urban distribution system source–network–load–storage in the context of high-penetrated building-integrated resources. In this model, source–network–load–storage resources are cost-optimally planned, including the lines, soft open point (SOP), building-integrated photovoltaics (BIPVs), building-integrated wind turbine (BIWT), building-integrated energy storage system (ESS), etc. To enhance fault recovery capability during extreme faults, fault scenarios are incorporated into the distribution system operation via coupled multiple recovery stages. The resilience-oriented planning is a thorny problem due to its source–network–load–storage couplings, normal-fault couplings, etc. The original resilience-oriented planning is reformulated as a mixed-integer linear programming (MILP) problem, which can then be solved with a two-stage method and evaluated via a multi-dimensional evaluation metrics. The proposed planning methodology is benchmarked over a Portugal 54-node urban distribution system to verify the superiority and effectiveness on the system economy and resilience levels. Case studies show that the proposed methodology can exploit the optimal synergies of different source–network–load–storage components and enhance system dispatchability.

Multi-dimensional evaluation of BIPV installations: Development of a tool to assess the performance as building component and electricity generator

The demand for building-integrated photovoltaics is constantly increasing, which is reflected in an increasing number of innovative BIPV products on the market and attractively implemented BIPV installations. To support architects, system developers, and other stakeholders involved in the planning of new BIPV projects, the experts of IEA-PVPS Task 15 have developed a multi-dimensional assessment tool based on the experiences and learnings of already installed BIPV-projects. The creation of a comprehensive, interdisciplinary evaluation methodology makes it possible to compare the multi-dimensional performance of existing BIPV systems, to derive strengths and weaknesses and to use this knowledge to plan application-optimized new BIPV systems. In a systematic step-by-step development process, four performance categories were defined: energy-related, economic, environmental and optical/visual. After defining the relevant performance indicators per category, a numerical rating system was established. In addition, a classification scheme for all relevant BIPV installation types was defined. Initial analyses were performed by a group of experts on several case studies of BIPV-roofs, facades and external devices in order to test and validate the methodology and approaches. Multiple iterations were required to optimize the methodology, but issues such as (i) lack of data availability for full project assessment or (ii) objectivity in visual assessments exist and will remain demanding. The research work also identified challenges and limitations in the context of pioneering and pilot building-integrated photovoltaics (BIPV) projects, which often used newly developed, immature or early-stage technologies at the time of their construction. The evaluation results of such lighthouse projects can vary significantly from those of BIPV installations using standardized products and well-established processes.

Environmental performance analysis of textile envelope integrated flexible photovoltaic using life cycle assessment approach

The textile envelope integrated flexible photovoltaic (TE-FPV) system is an emerging technology to promote building sustainability due to its lightweight structure, textile recovery easily, and renewable energy production. We develop six novel TE-FPV prototypes to determine their advantages of environmental performance. Especially, the systems with the solar cells directly printed on the textile are designed to show the promising sustainability prospect. Their environmental performances are conducted by a cradle-to-cradle life cycle assessment, and the results are compared to traditional building integrated photovoltaic (BIPV) technologies. The life cycle inventories of some textiles and solar cells are the first time to be developed. Based on the inventories, life cycle impact assessment is implemented to figure out environmental impacts in various categories. Furthermore, uncertainty analyses and sensitivity analyses are performed to unmask the effects of parameters on the fluctuation of environmental indicators. The results present that most of TE-FPV systems perform more sustainable and more recyclable over the traditional BIPV systems. The organic solar cell is unfavorable for the TE-FPV systems due to its low power conversion efficiency and short lifespan. ETFE facade integrated perovskite solar cell systems can refund the investment of greenhouse gas emission even on the north orientation, showing vast prospective potential in environmental performances. This work contributes significantly required environmental quantifications to promote the advancement of TE-FPV systems.

Analysis and Selection of Optimal Perovskite/Silicon Tandem Configuration for Building Integrated Photovoltaics Based on Their Annual Outdoor Energy Yield Predicted by Machine Learning

Accurate estimation of annual output energy yield () for perovskite/silicon (PSK/cSi) tandem solar cells is pivotal in assessing their suitability for building‐integrated photovoltaics (BIPV). This study pioneers five machine learning models of ensembles of trees, Gaussian process regressions, regression trees, support vector machines, and artificial neural networks (ANN) to predict output power density and compute for 2T, 3T, and 4T PSK/cSi tandem configurations in Japan's outdoor conditions. Seven predictive inputs of visible‐light solar irradiance, near‐infrared‐light solar irradiance, incident solar spectrum angle, solar module temperature, perovskite thickness, perovskite bandgap, and terminal of tandem configuration (T) drive the machine learning models. These models optimize predictions using k‐fold cross‐validation and Bayesian algorithms, showcasing superior precision in prediction compared to prior models. The ANN model emerges as the best model, displaying the minimal error in predicting , used to estimate across five Japanese locations (Gifu, Naganuma, Okinoerabu, Tosu, and Tsukuba). Results from these locations in blue‐rich solar spectrum zones identify the 4T PSK/cSi tandem configuration, featuring the most outstanding mean maximal (93.63, 263.02, 153.59, and 91.75 kWh m−2 for the east, rooftop, south, and west directions), as the prime candidate for BIPV applications.

Unveiling the Potential of Two-Terminal Perovskite/Organic Tandem Solar Cells: Mechanisms, Status, and Challenges.

Perovskite/organic tandem solar cells (PO-TSCs) demonstrate exceptional suitability for emerging applications such as building-integrated photovoltaics, wearable devices, and greenhouse farming. By leveraging the distinctive attributes of perovskite and organic materials, which encompass expanded solar spectrum utilization, chemically benign solubility, and soft nature, PO-TSCs position themselves as ideal candidates for high-performance semi-transparent photovoltaics (ST-PVs). Despite these advantages, their development significantly lags behind other perovskite-based counterparts, such as perovskite/perovskite, perovskite/silicon, and perovskite/Cu(In, Ga)Se2. To address existing challenges and unlock the full potential of PO-TSCs, an exploration of the fundamental mechanisms governing tandem photovoltaic devices is embarked. Delving into critical aspects such as charge generation/separation, energy level alignment, and material choices becomes pivotal for optimizing PO-TSC performance. The investigation of monolithic two-terminal PO-TSCs offers insights into achievements and barriers, recognizing the competitive landscape with other TSC counterparts. Further scrutiny of perovskite absorbers and organic absorbers in TSCs reveals strategies aimed at enhancing stability and efficiency. The discussion extends to interconnection layers, elucidating their role in optimizing light transmission and balancing carrier recombination. In conclusion, a compelling outlook on the dynamic landscape of PO-TSCs is presented, highlighting the remarkable efficiency progression and signaling their potential to revolutionize solar energy harvesting technologies.

Massive Solar PV Potential in Sri Lanka

Sri Lanka is facing an energy crisis due to insufficient exploitation of renewable energy resources and high reliance on imported fossil fuels. Building-integrated PV (BIPV) systems are one approach that provides various benefits in countries with limited land areas and congested metropolitan regions for ensuring energy security. This study was conducted to evaluate the rooftop solar PV capacity and yearly electricity generation potential in selected provinces in Sri Lanka. The study found 115 km2 of rooftop area for solar PV installation in four Sri Lankan provinces; Sabaragamuwa, Western, Northern, and North Central with approximately 25 GW of solar PV installation capacity could lead to annual electricity generation of 45 TWh which could reduce carbon emissions by 20 million tCO 2 per year.

Doping with KBr to Achieve High-Performance CsPbBr3 Semitransparent Perovskite Solar Cells.

Wide-bandgap semitransparent perovskite photovoltaics are emerging as one of the ideal candidates for building-integrated photovoltaics (BIPV). However, surface defects in inorganic CsPbBr3 perovskite prepared by vapor deposition severely limit the optoelectronic performance of perovskite solar cells. To address this issue, a strategy of doping a trace amount of KBr into perovskite by vapor deposition is adopted, effectively improving the quality of the film, reducing surface defect concentration, and enhancing the transportation and extraction of charge carriers. Simultaneously, fully physical vapor deposition technology is employed to fabricate perovskite solar cells with an average visible light transmittance of 44%. These devices exhibited an ultrahigh open-circuit voltage of 1.55 V and a superior power conversion efficiency (PCE) of 7.28%, demonstrating excellent moisture and heat resistance. Moreover, the corresponding 5 cm × 5 cm modules achieve a PCE of 5.35% with great thermal insulation capability. This work provides an approach for fabricating highly efficient all-inorganic perovskite solar cells with high average visible light transmittance, demonstrating new insights into their application in building-integrated photovoltaics.