High Average Transmittance Research Articles

Superhydrophobic films with high average transmittance in infrared and visible range prepared by iCVD technology

Superhydrophobic high-transmittance antireflection coatings (ARCs) have significant potential for applications in optical devices such as microscope lenses, as well as in daily life for windows and glasses. However, current technologies encounter challenges in achieving superhydrophobicity on surfaces of ARCs. Here, we successfully combine the initiated chemical vapor deposition (iCVD) process technology with surface structuring to obtain a wide-spectrum transmission-enhanced coatings exhibiting self-cleaning and superhydrophobic properties. Compared with the bared substrate, the average transmittance of the worm-like/nanocones structure increases from 93.0 % to 95.1 %. Furthermore, an impressive water contact angle of 177.1° and a sliding angle of less than 1.0° are achieved. Moreover, the transmittance and hydrophobic properties can be easily adjusted by manipulating morphology of the film. The formation mechanism and fabrication processes of nanocones and worm-like structures are comprehensively investigated for flexible adjustment of the film properties. This provides a practical solution for the application of ARCs in various scenarios.

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%.

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.

Period induced reflectance tuning in transparent gold metasurfaces

Gold (Au) nanodisk arrays are modeled and fabricated for tunable near infrared reflectance with high visible transmittance. Simulations are performed in the visible and near infrared regimes between 400 and 2000 nm with varying period of nanostructures. A progressive increase in period of up to three times the diameter of the nanodisks on polymer and quartz substrates is presented. As a result, an increase in visible transmittance with a decrease in near infrared reflectance peak intensity is observed. Modeling results exhibit a high average visible transmittance of 91.5% (400–700 nm) and average reflectance of 62.9% (750–2000 nm) with diameter (D) variations from D=120 nm to D=500 nm with a period (P) equal to twice the diameter, P=2D for a polymer substrate. Electric field intensities exhibit an increase with a decrease in the period between individual nanostructures for constant unit cell dimensions. Alongside simulations, electron beam lithography and evaporation processes are utilized for the patterning and fabrication. Optical characterizations including scanning electron microscopy (SEM) and atomic force microscopy (AFM) of selected metasurfaces on quartz are performed. For a specific period and diameter, the fabricated metasurfaces exhibit near infrared reflectance having a good agreement with the simulated results about plasmonic wavelengths. Such metasurfaces offer potential to be deployed for applications that require selective reflectance intensities in the near infrared range with high visible transmittance, such as controlled environment agriculture (CEA) or multi spectral near infrared sensing. With tunability over a broadband (750–2500 nm), this simple and fabrication-friendly model may be used as a theoretical guide in quantifying specific design parameters with varying light intensity configurations.

Solid Additive Dual-Regulates Spectral Response Enabling High-Performance Semitransparent Organic Solar Cells.

Semi-transparent organic solar cells (ST-OSCs) possess significant potential for applications in vehicles and buildings due to their distinctive visual transparency. Conventional device engineering strategies are typically used to optimize photon selection and utilization at the expense of power conversion efficiency (PCE); moreover, the fixed spectral utilization range always imposes an unsatisfactory upper limit to its light utilization efficiency (LUE). Herein, a novel solid additive named1,3-diphenoxybenzene (DB) is employed to dual-regulate donor/acceptor molecular aggregation and crystallinity, which effectively broadens the spectral response of ST-OSCsin near-infrared region. Besides, more visible light is allowed to pass through the devices, which enables ST-OSCs to possess satisfactory photocurrent and high average visible transmittance (AVT) simultaneously. Consequently, the optimal ST-OSC based on PP2+DB/BTP-eC9+DB achieves a superior LUE of 4.77%, representing the highest value within AVT range of 40-50%, which also correlates with the formation of multi-scale phase-separated morphology. Such results indicate that the ST-OSCs can simultaneously meet the requirements for minimum commercial efficiency and plant photosynthesis when integrated with the roofs of agricultural greenhouses. This work emphasizes the significance of additives to tune the spectral response in ST-OSCs, and charts the way for organic photovoltaics in economically sustainable agricultural development.

Highly-efficient full-color holographic movie based on silicon nitride metasurface

Abstract Metasurface holograms offer various advantages, including wide viewing angle, small volume, and high resolution. However, full-color animation of high-resolution images has been a challenging issue. In this study, a full-color dielectric metasurface holographic movie with a resolution of 2322 × 2322 was achieved by spatiotemporally multiplexing 30 frames with blue, green, and red color channels at the wavelengths of 445 nm, 532 nm, and 633 nm at the maximum reconstruction speed of 55.9 frames per second. The high average transmittance and diffraction efficiency of 92.0 % and 72.7 %, respectively, in the visible range, were achieved by adopting polarization-independent silicon nitride waveguide meta-atoms, resulting in high color reproducibility. The superposition of three wavelengths was achieved by adjusting the resolutions and positions of target images for each wavelength while maintaining the meta-atom pitch constant. The improvement in diffraction efficiency was brought about by the optimization of etching conditions to form high-aspect vertical nanopillar structures.

Organohydrogel-based transparent terahertz absorber via ionic conduction loss

The fast-growing terahertz technologies require high-performance terahertz absorber for suppressing electromagnetic interference. Since the dissipation mechanism in terahertz band usually focuses on electronic conduction loss, almost all terahertz absorbers are constructed with electronically conducting materials being opaque, which limits their applications in scenarios requiring high visible transmittance. Here, we demonstrate a transparent terahertz absorber based on permittivity-gradient elastomer-encapsulated-organohydrogel. Our organohydrogel-based terahertz absorber exhibits a high absorbing property (average reflection loss of 49.03 dB) in 0.5–4.5 THz band with a thin thickness of 700 μm and a high average visible transmittance of 85.51%. The terahertz absorbing mechanism mainly derives from the ionic conduction loss of the polar liquid in organohydrogel. Besides, the hydrophobic and adhesive elastomer coating endows this terahertz absorber high absorbing stability and interfacial adhesivity. This work paves a viable way to designing transparent terahertz absorbers.

Envisioning the future: optically transparent metasurface-based solar thermophotovoltaic with high conversion efficiency

Transparent solar thermo-photovoltaic (TPV) technology combines visible transparency and solar energy conversion. They are developed for their potential applications in buildings and vehicles windows, where conventional opaque solar cells may not be feasible. TPV’s offer a promising solution to harness solar energy without compromising aesthetics or functionality of transparent surfaces. Broadband absorption at UV and IR frequencies and simultaneous transmission at visible frequencies can be achieved by fabricating metamaterials that employ semi-conducting oxides. In this study, an optically transparent metasurface (OTM) based STPV composed of indium tin oxide (ITO) is introduced as the transparent metal and ZnS as a substrate layer. Our design offers a cost-effective and scalable solution for large-scale fabrication. The designed OTM structure exhibits exceptional absorption capabilities, achieving an absorption rate of up to 99% in the UV region. Additionally, it achieves over 90% absorptivity in the far infrared range and maintains a high average transmittance at visible frequencies. Furthermore, the absorption remains consistently high, exceeding 90%, even when the incident angle is less than 70° for both TE and TM polarization waves. This innovative design holds promise for various applications requiring high-performance transparent metasurface absorbers/emitters. The proposed transparent metasurface based STPV holds great potential for efficient utilization in combined solar/thermal conversion systems.

Van Der Waals Semiconductor Based Omnidirectional Bifacial Transparent Photovoltaic for Visual-Speech Photocommunication.

Omnidirectional photosensing is crucial in optoelectronic devices, enabling a wide field of view (wFoV) and leveraging potential applications for the Internet of Things in sensors, light fidelity, and photocommunication. The wFoV helps overcome the limitations of line-of-sight communication, and transparent photodetection becomes highly desirable as it enables the capture of optical information from various angles. Therefore, developing a photoelectric device with a 360° wFoV, ultra sensitivity to photons, power generation, and transparency is of utmost importance. This study utilizes a heterojunction of van der Waals SnS with Ga2 O3 to fabricate a transparent photovoltaic (TPV) device showing a 360° wFoV with bifacial onsite power production. SnS/Ga2 O3 heterojunction preparation consists of magnetron sputtering and is free from nanopatterning/nanostructuring to achieve the desired wFoV window device. The device exhibits a high average visible transmittance of 56%, generates identical power from bifacial illumination, and broadband fast photoresponse. Careful analysis of the device shows an ultra-sensitive photoinduced defect-modulated heterojunction and photocapacitance, revealed by the impedance spectroscopy, suggesting photon-flux driven charge diffusion. Leveraging the wFoV operation, the TPV embedded visual and speech photocommunication prototype demonstrated, aiming to help visually and auditory impaired individuals, promising an environmental-friendly sustainable future.

Amorphous transparent conducting oxide for van-der Waals semiconductor bifacial transparent photovoltaics

Building integrated photovoltaic systems have necessitated the development of transparent photovoltaics (TPV). Transparent conducting oxides (TCO) play a vital role in charge carrier transport in TPVs. Their high transparency, electrical conductivity, and tunable work function make them imperative for TPV applications. Here in this work, we develop a room-temperature grown amorphous-InZnO (a-IZO) thin film for the bottom electrode for TPV. The a-IZO film has demonstrated a high average visible transmittance of 84 % over commercial F:SnO2 (FTO) substrate. A TPV with wide band gap oxide (n-Ga2O3) and a very thin layer of van der Waals material (p-SnS) was fabricated over the a-IZO thin film and commercial FTO substrate for better comparison. A significant enhancement in the current density, open-circuit voltage, and fill factor was recorded. The device with a-IZO electrode showed a bifacial power production feature with a power conversion efficiency of 3.9 % in contrast to FTO electrode-based TPV with 1.5 %. The a-IZO-based TPV also showed a good UV–vis photodetection ability with the highest responsivity of 93 mA/W and the fastest response time of 400 μs. This work suggests that enhanced photovoltaic and photodetection performance is possible using an optimum electrode design.

Semitransparent Perovskite Solar Cells with an Evaporated Ultra‐Thin Perovskite Absorber

AbstractMetal halide perovskites are of great interest for application in semitransparent solar cells due to their tunable bandgap and high performance. However, fabricating high‐efficiency perovskite semitransparent devices with high average visible transmittance (AVT) is challenging because of their high absorption coefficient. Here, a co‐evaporation process is adopted to fabricate ultra‐thin CsPbI3 perovskite films. The smooth surface and orientated crystal growth of the evaporated perovskite films make it possible to achieve 10 nm thin films with compact and continuous morphology without pinholes. When integrated into a p‐i‐n device structure of glass/ITO/PTAA/perovskite/PCBM/BCP/Al/Ag with an optimized transparent electrode, these ultra‐thin layers result in an impressive open‐circuit voltage (VOC) of 1.08 V and a fill factor (FF) of 80%. Consequently, a power conversion efficiency (PCE) of 3.6% with an AVT above 50% is demonstrated, which is the first report for a perovskite device of a 10 nm active layer thickness with high VOC, FF and AVT. These findings demonstrate that deposition by thermal evaporation makes it possible to form compact ultra‐thin perovskite films, which are of great interest for future smart windows, light‐emitting diodes, and tandem device applications.

A comparative study of photoelectric performance of Ga2O3 solar-blind photodetectors with symmetric and asymmetric electrodes

Gallium oxide (Ga2O3) thin films were deposited on quartz substrates under different oxygen flow ratios (O2/[O2+Ar], 0%−5%) by radio-frequency (RF) magnetron sputtering technique followed by thermal annealing at 900 °C for 2 h under N2 atmosphere. The influence of the oxygen concentration on the structural and optical characteristics of Ga2O3 thin films was investigated. The Ga2O3 thin films prepared under an oxygen flow ratio of 1% exhibited optimum crystal quality and the lowest oxygen vacancy (VO) concentration according to X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) investigations. All as-prepared polycrystalline Ga2O3 thin film samples exhibited high average transmittance above 87.8% in the visible spectral region and the 0% and 1% thin films had optical bandgap energies of about 4.9 eV. We also fabricated metal−semiconductor−metal (MSM) photodetectors based on 1% Ga2O3 thin films by employing pairs of Ni−Ni symmetrical or Ni−Al asymmetrical interdigitated electrodes. The Ni−Ni photodetector had a high on/off current ratio (Ion/Ioff > 105), a responsivity of 88.7 mA/W, and specific detectivity of 4.81×1010 J at 10 V bias under ultraviolet light-C (UVC) illumination, and the Ni−Al photodetector exhibited self-driven behavior along with short rise and fall times (0.45 s and 0.69 s, respectively).

Solution Processed Semi-Transparent Organic Solar Cells Over 50% Visible Transmittance Enabled by Silver Nanowire Electrode with Sandwich Structure.

Photovoltaic windows with easy installation for the power supply of household appliances have long been a desire of energy researchers. However, due to the lack of top electrodes that offer both high transparency and low sheet resistance, the development of high-transparency photovoltaic windows for indoor lighting scenarios has lagged significantly behind photovoltaic windows where privacy issues are involved. Addressing this issue, this work develops a solution-processable transparent top electrode using sandwich structure silver nanowires, realizing high transparency in semi-transparent organic solar cells. The wettability and conducting properties of the electrode are improved by a modified hole-transport layer named HP. The semi-transparent solar cell exhibits good see-through properties at a high average visible transmittance of 50.8%, with power conversion efficiency of 7.34%, and light utilization efficiency of 3.73%, which is the highest without optical modulations. Moreover, flexible devices based on the above-mentioned architecture also show excellent mechanical tolerance compared with Ag electrode counterparts, which retains 94.5% of their original efficiency after 1500 bending cycles. This work provides a valuable approach for fabricating solution-processed high transparency organic solar cells, which is essential in future applications in building integrated photovoltaics.

The effect of thickness on the optical and electrical properties of Hf doped indium oxide thin films

The doping of Hf has great potential to adjust the optical and electrical properties of In2O3 films, which has rarely been reported. In this paper, Hf-doped indium oxide films (IHFO) with excellent optical (average transmittance: 95.81%) and electrical properties (resistivity: 7.1 × 10−4 Ω cm) were deposited by RF sputtering on the glass substrate. X-ray photoelectronic spectra (XPS) showed that Hf4+ substituted In3+, resulting in an increase in carrier concentration and thus decreased resistivity. The X-ray diffraction (XRD) and Scanning electron microscopy (SEM) indicated that the change in the preferred orientation of IHFO film from (400) to (222) leads to different shape grains, which are associated with nuclei merging due to thickness increase. As the optical path of the visible light in film increase with film thickness, the film's visible light absorption is enhanced, resulting in the average transmittance of the films decreasing from 95.81% to 87.68%. Considering the effect of thickness on optical and electrical properties, the IHFO film at a thickness of 893 nm exhibits the highest FOM value of 2.85 × 10−2 Ω−1 with high average transmittance (89.84%) and low sheet resistance(12 Ω/sq). This result indicates that the IHFO film deposited with optimal thickness can be an alternative for high-performance TCO in various optoelectronic fields.

Longitudinal Through-Hole Architecture for Efficient and Thickness-Insensitive Semitransparent Organic Solar Cells.

Semi-transparent organic solar cells (ST-OSCs) have great potential for application in vehicle- or building-integrated solar energy harvesting. Ultrathin active layers and electrodes are typically utilized to guarantee high power conversion efficiency (PCE) and high average visible transmittance (AVT)simultaneously; however, such ultrathin parts are unsuitable for industrial high-throughput manufacturing. In this study, ST-OSCs are fabricated using a longitudinal through-hole architecture to achieve functional region division and to eliminate the dependence on ultrathin films. A complete circuit that vertically corresponds to the silver grid is responsible for obtaining high PCE, and the longitudinal through-holes embedded in it allow most of the light to pass through,where the overall transparency is associated with the through-hole specification rather than the thicknesses of active layer and electrode. Excellent photovoltaic performance over a wide range of transparency (9.80-60.03%), with PCEs ranging from 6.04% to 15.34% is achieved. More critically, this architecture allows printable 300-nm-thick devices to achieve a record-breaking light utilization efficiency (LUE) of 3.25%, and enables flexible ST-OSCs to exhibit better flexural endurance by dispersing the extrusion stress into the through-holes. This study paves the way for fabricating high-performance ST-OSCs and shows great promise for the commercialization of organic photovoltaics.

Highly conductive and broadband transparent Zr‐doped In2O3 as the front electrode for monolithic perovskite/silicon tandem solar cells

AbstractPerovskite/silicon tandem solar cells show great potential for commercialization because of their high power conversion efficiency (PCE). The optical loss originated from the transparent electrode is still a challenge to further improve the PCE of perovskite/silicon tandem solar cells. Here, we developed zirconium‐doped indium oxide (IZrO), a material with low resistivity and high transmittance sputtered at room temperature. It possesses a high mobility of 29.6 cm2/(V·s), a low resistivity of 3.32 × 10−4 Ω·cm, and a low sheet resistance of 25.55 Ω·sq−1 as well as a high average transmittance of 81.55% in a broadband of 400–1200 nm. Moreover, the work function (WF = 4.33 eV) matches well with the energy level of Ag electrode and SnO2 buffer layer in the P‐I‐N type tandem device. Compared with the previous zinc‐doped indium oxide (IZO) transparent electrode device, the absolute efficiency of perovskite/silicon tandem devices based on IZrO electrode is about 0.6% higher. The champion P‐I‐N type perovskite/silicon tandem solar cells employing IZrO as the front conducts show efficiency of 28.28% (area of 0.5036 cm2).

In-depth analysis on PTB7 based semi-transparent solar cell employing MoO3/Ag/WO3 contact for advanced optical performance and light utilization

Novel semi-transparent organic solar cells (ST-OSC) can be designed with high average visible transmittance (AVT) while at the same time exhibiting superior photovoltaic performance. This reach requires their design to be based not only on conventional window applications but also on functional industrial applications that require exceptional optical performance. In ST-OSC, high AVT can be achieved by photonic-based dielectric/metal/dielectric (DMD) transparent contact engineering. Functional optical modification can also be made with a fine-tuned design of DMD that includes a light management engineering-based approach. Thus, ST-OSCs can be suitable for aesthetic, colourful and decorative industrial windows that provide natural lighting. In this study, we determined optimal ST-OSCs based on a novel PTB7:PC71BM polymer blend with MoO3/Ag/WO3 asymmetric DMD top contact by examining extraordinary optical properties such as AVT, colour rendering index, correlated colour temperature and colour perception over 10 thousand designs. In addition to determining the optimality and extraordinary optical limits for PTB7, we also evaluated the photon-harvesting and photovoltaic performance of ST-OSCs from external quantum efficiency and quantum utilization efficiency. In optimal situations, ST-OSCs offering 48.75% AVT, 99.08 CRI, and sky-blue colours were designed and determined to generate short-circuit current densities of 9.88 mA·cm−2, 13.64 mA·cm−2, and 13.06 mA·cm−2, respectively.

Highly water dispersible collagen/polyaniline nanocomposites with strong adhesion for electrochromic films with enhanced cycling stability

Electrochromic materials have attracted extensive attention recently due to their versatile applications in smart windows, displays, antiglare rearview mirrors, and so on. Herein we report a new electrochromic composite prepared from collagen and polyaniline (PANI) through a self-assembly assisted co-precipitation method. The introduction of hydrophilic collagen macromolecules into PANI nanoparticles makes the collagen/PANI (C/PANI) nanocomposite obtain excellent dispersibility in water, which provides good environmental-friendly solution processability. Furthermore, the C/PANI nanocomposite exhibits excellent film-forming properties and adhesion to the ITO glass matrix. The resulting electrochromic film of the C/PANI nanocomposite displays significantly improved cycling stability compared with the pure PANI film after 500 coloring-bleaching cycles. On the other hand, the composite films also exhibit yellow, green and blue polychromatic properties at different applied voltages and high average transmittance at the bleaching state. The C/PANI electrochromic material illustrates scaling potential for the application of electrochromic devices.

Solution-processed polymer bilayer heterostructures as hole-transport layers for high-performance opaque and semitransparent organic solar cells

Interfacial layer materials such as hole-transport layers (HTLs) are critical to realizing high-performance organic solar cells (OSCs). However, most OSCs are relying on a prominent HTL material of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with the hygroscopic and acidic feature, which induces poor device stability and limited power conversion efficiencies (PCEs). Here, a novel type of HTLs is developed by combining intrinsically stable poly(triarylamine) (PTAA) with modified PEDOT:PSS for efficient opaque and semitransparent OSCs with good stability. Using diluted solution processing, isopropanol-diluted PEDOT:PSS (ID-PEDOT:PSS) is deposited onto hydrophobic PTAA to improve interfacial compatibility, thereby forming a fitted polymer bilayer heterostructure HTL of PTAA/ID-PEDOT:PSS with high film quality and good transparency. For applications in OSCs with a nonfullerene acceptor (M36), the resulting opaque devices deliver an improved PCE of 14.45%, much higher than 5.72% and 13.21% for the pure PTAA and PEDOT:PSS HTLs-based devices, respectively. The stability of the PTAA/ID-PEDOT:PSS-based OSCs is improved simultaneously, where a normalized PCE for the device after storage over three months retains above 80%, much better than those of devices with other two HTLs. This novel HTL is further used to achieve efficient and stable semitransparent M36-based devices for the first time, exhibiting an outstanding PCE of 12.34% at a high average visible transmittance of 25.56%. Our findings provide an excellent semiconducting interlayer candidate to develop promising opaque and semitransparent OSCs.

High Efficiency Transparent and Semi‐Transparent Photovoltaics Based on a Layer‐By‐Layer Deposition

Transparent and semitransparent photovoltaics offer an exciting opportunity to integrate existing infrastructure with renewable energy. Organic photovoltaics (OPVs) are key enablers for wavelength‐selective transparent photovoltaics (TPVs) because of their selective absorption in the near‐infrared (NIR) that enables simultaneously high power conversion efficiency (PCE) and average visible transmittance (AVT). The recent rise of OPVs and TPVs has been accelerated in large part by the development of nonfullerene acceptors (NFAs) as highly adaptable deep NIR harvesting materials. Herein, sequential layer‐by‐layer (LBL) deposition of a selectively NIR absorbing nontraditional acceptor polymer is paired with a NIR absorbing donor IEICO‐4F that is typically considered an NFA via solvent orthogonality. With detailed optimization of the active layers and top electrode, semi‐transparent photovoltaics with a PCE of 8.8%, AVT of 40.9%, and a light utilization efficiency of 3.6% are demonstrated. The LBL approach enables explicit optical modeling of the device structure to extract exciton diffusion lengths >100 nm for both the polymer and IEICO‐4F with a transition in charge collection length regimes dependent on the acceptor thickness. Furthermore, the LBL deposition technique enables an investigation of the full range of polymer thickness and its impact on power generation and optical performance.