Energy Level Mismatch Research Articles

Design and Device Modeling of Lead Free CsSnI3 Perovskite Solar Cell

Research of lead-free Perovskite based solar cells has gained speedy and growing attention with urgent intent to eliminate toxic lead in Perovskite materials. The main purpose of this work is to supplement the research progress with comparative analysis of different lead-free Perovskite based solar cells by numerical simulation method using solar cell capacitance simulator (SCAPS-1D) software. The environmental friendliness and excellent thermal stability proves Cesium Tin Iodide (CsSnI3) as one of the promising materials for the commercialization of the Perovskite solar cells. However, CsSnI3 solar cells suffer from poor efficiency due to having low open-circuit voltage, VOC attributed to poor absorber film quality as well as energy level mismatch at the interfaces between different layers like transparent front contact. The architecture of the solar cell is n-i-p device structure acts as light CsSnI3 absorber active layer, TiO2 as electron transport layer and Spiro-OMeTAD as hole transport layer with device structure FTO/ TiO2/CsSnI3 / Spiro-OMeTAD /Au. The open circuit voltage Voc, short circuit current density Isc, fill factor and power conversion efficiency Voc=1.09V, Jsc=28.85mA/cm2, FF=88.65%, eta=28.09%, V_MPP=0.99V, J_MPP=28.15 mA/cm2 respectively.

Effect of CZTS/CCZTS Stacked Structures Prepared through Split-Cycle on the Performance of Flexible Solar Cells

Flexible CZTS solar cells have attracted significant attention in recent years owing to their high earth element composition and high photovoltaic conversion efficiency. However, these cells are associated with limitations common in compound thin-film solar cells, such as heterojunction interface combination centers, material defects, and energy level mismatch. In the current study, a green and simple solution spin-coating method is proposed for the preparation of flexible solar cells with multicycle CZTS/CCZTS absorber stacked structures to effectively circumvent the limitations of flexible devices. The results showed that the optimized Zn/Cd ratio results in CCZTS films with large grain longitudinal growth. However, lots of small broken grains were formed at the bottom of the absorber owing to the large lattice spacing, leading to the formation of cell leakage channels. The surface morphology of the absorber film was improved by preparing a stacked structure of CZTS and CCZTS with different periods while suppressing the longitudinal grain delamination. The stacked structure also helps to match the energy band of CZTS/CCZTS/CdS heterojunction. The top layer of CCZTS forms a buffered “energy band ladder” in the energy band of the CZTS/CdS heterojunction, thus suppressing the rapid carrier recombination caused by the Cliff-type energy band bending. A flexible solar cell was thus prepared to obtain a high photoelectric conversion efficiency of 6.51%, and the cells showed excellent resistance to mechanical bending.

Bright and efficient sky-blue perovskite light-emitting diodes via doping of π-conjugated molecule tetraphenylethylene

As a star material, to date, hybrid perovskites with green and red emission show high photoluminescence quantum yields, and the external quantum efficiency (EQE) of perovskite light-emitting diodes (PeLEDs) has exceeded 20%. However, due to the poor film quality and large energy level mismatch, the performance of blue PeLEDs still lags far behind. Herein, a π-conjugated tetraphenylethylene (TPE) doping strategy is demonstrated to improve both the efficiency and stability of sky-blue PeLEDs. With proper TPE doping, the defects are passivated and the energy levels of multi-cation perovskite are elevated, resulting in a smooth and dense film with high PLQY (∼27.8%). The champion PeLED shows a brightness of 12,963 cd/cm 2 at 484 nm and maximum EQE of 6.97%. Moreover, after TPE doping, the operational stability of the PeLED increases from 290 s to 960 s under continuous working condition. The π-conjugated molecule doping strategy could open up a new avenue for the design of high-performing blue PeLEDs. • A high-quality sky-blue-emitting multi-cation perovskite film doped by tetraphenylethylene is prepared. • By introduction of TPE, the defects are passivated and the energy levels of perovskite are elevated. • The optimized sky-blue PeLED exhibits high brightness and improved device stability under continuous operation.

Electroactive Ionenes: Efficient Interlayer Materials in Organic Photovoltaics.

ConspectusOrganic photovoltaics (OPVs) have the advantages of being lightweight, mechanically flexible, and solution-processable over large areas, and for decades, they have been the focus of the academic and industrial communities. Recent progress in the design of high-performance organic semiconductors and device optimization has promoted solar cell efficiencies of up to 19%, showing great promise for commercialization. Optimally designed OPVs are achieved using a bicontinuous interpenetrating network of donor and acceptor materials in between two charge-collecting electrodes. Charge extraction and transport between metal electrodes and organic semiconductors are crucial to device operation. The energy-level mismatch when metal electrodes and organic semiconductors are in contact usually induces additional energy barriers and resultant inefficient charge transport and collection, leading to charge carrier recombination at the interface and inferior device performance. To align energy levels at the interface, interlayer materials and their integration into devices have emerged as a widely used strategy to promote the performance of solar cell devices. Interlayer materials have the ability to modify the work functions (WFs) of metal electrodes, holding the potential to enhance the built-in electrostatic field (Vbi) of the devices and suppress the charge recombination loss, which is beneficial to improving the open circuit voltage (VOC), short circuit current density (JSC), and fill factor (FF) of the solar cells.Organic interlayer materials have recently come into focus for fundamental study and practical development because of their diverse molecular design and superior solution processability. Tremendous effort has been devoted to exploring novel organic interlayer materials to achieve all-solution-processed multilayer solar cells. Such interlayer materials usually have orthogonal solubilities relative to the photoactive layer materials, working as multifunctional interfacial layers to manipulate the mechanical and electrical contacts in solar cell devices. Ionenes are a unique class of polyelectrolytes wherein the ionic species reside within the polymer backbone rather than as pendant groups. In ionenes, the charge density is high in comparison to that of other polyelectrolytes, and the periodicity of the charges is easily controlled, providing a tunable density of dipole moments. Ionenes can be readily synthesized from 3° diamines and α,ω-dihaloalkanes to generate polymer chains of ammonium cations connected by flexible hydrocarbon linkages with mobile anions. However, the requisite building blocks of ionenes are not limited to such molecules. Recent advances in combining ionenes with conjugated molecules to generate electroactive ionenes have catalyzed a great amount of interest in such polymers for organic electronic devices.In this Account, we first introduce the molecular design and synthesis of electroactive ionenes. Following this, we will discuss the mechanism and effect of ionenes on the modification of metal electrodes. We then review the strategies for controlling the morphology of ionene interlayers. Finally, we compare the doping effect, conductivity, and charge transport of some representative ionenes and their performance as interlayers in solar cell devices. We present our current understanding based on recent progress and outstanding issues of interlayer materials in OPVs and to propose future directions and opportunities.

Unveiling Charge Carrier Recombination, Extraction, and Hot-Carrier Dynamics in Indium Incorporated Highly Efficient and Stable Perovskite Solar Cells.

Perovskite solar cells (PSCs) have been propelled into the limelight over the past decade due to the rapid‐growing power conversion efficiency (PCE). However, the internal defects and the interfacial energy level mismatch are detrimental to the device performance and stability. In this study, it is demonstrated that a small amount of indium (In3+) ions in mixed cation and halide perovskites can effectively passivate the defects, improve the energy‐level alignment, and reduce the exciton binding energy. Additionally, it is confirmed that In3+ ions can significantly elevate the initial carrier temperature, slow down the hot‐carrier cooling rate, and reduce the heat loss before carrier extraction. The device with 1.5% of incorporated In3+ achieves a PCE of 22.4% with a negligible hysteresis, which is significantly higher than that of undoped PSCs (20.3%). In addition, the unencapsulated PSCs achieve long‐term stability, which retain 85% of the original PCE after 3,000 h of aging in dry air. The obtained results demonstrate and promote the development of practical, highly efficient, and stable hot‐carrier‐enhanced PSCs.

Design and simulation of efficient tin based perovskite solar cells through optimization of selective layers: Theoretical insights

Within a decade, Perovskite solar cells (PSCs) have attained an efficiency of 25.8%. PSCs lack commercialization due to two main factors: (i) poor device stability (ii) toxicity. The tin (Sn) is a possible candidate to substitute toxic lead (Pb) in traditional PSCs; however, the performance of Sn-based PSCs is 13%, much lower than Pb-based PSCs due to several aspects. In this work, we have used drift-diffusion simulation to propose a pathway to improve the performance of lead-free PSCs using MASnI3 as a light harvester. The conventional charge selective layer, such as TiO2, requires high-temperature processing, which also is a major concern. As reported earlier, traditional transport layers contribute actively to the degradation of PSCs, affecting their stability. Therefore, we have used ZnO nanoparticles (NP) as electron transport material (ETM), and conducted an analysis using various organic and inorganic hole transport materials (HTMs) with spike and cliff structures. The impact of HTM thickness on the performance parameters of MASnI3 based PSCs with constant and variable charge acceptor concentrations was investigated. This work indicates that organic HTMs exhibit more thickness-dependent behavior than inorganic HTM for MASnI3 based PSCs. Furthermore, the suitable valence band offset (VBO) and barrier height at Perovskite/HTM and HTM/Back contact interfaces were studied for efficient energy level mismatch with absorber layer to boost the performance of MASnI3 based PSCs. The concept of selecting back contact for Sn-based PSCs using different HTMs was analyzed. The influence of temperature variation on the performance of PSCs using different HTM was analyzed. The hybrid configuration devices face the issue of interfacial recombination; thus, the impact of defect density at the HTM/MASnI3 interface on the performance of PSCs with various HTMs was investigated. Lastly, MASnI3 based PSC showed a power conversion efficiency (PCE) of 23.51% using the unmodified CuSCN based HTM and, CuI can also deliver an efficiency of 23.31% employed modified valence band energy level.

High-performance carbon-based CsPbI2Br perovskite solar cells via small molecule modification

All-inorganic CsPbI2Br perovskite material has attracted enormous attention for high-performance photovoltaics due to its excellent thermal stability and suitable bandgap. Furthermore, carbon-based CsPbI2Br perovskite solar cells (C-PSCs) not only further improve the thermal and moisture stability of the devices but also reduce production costs and simplify procedure processes. However, the usage of carbon electrodes introduces new problems, such as poor interface contact and energy level mismatch. Herein, the N-phenylthiourea (PTU) with S atom and N-phenylurea (PU) with O atom are applied for interface modification materials in C-PSCs. The atoms S and O can combine with Pb and enhance perovskite crystallinity as well as manage the energy level. Meanwhile, after passivation of PTU and PU, the defect state density of the perovskite layer is significantly reduced, thereby inhibiting the recombination of carriers. The Voc of the device with PTU increases from 1.12 V to 1.22 V, 9% improvement over the control device. The efficiency of CsPbI2Br C-PSCs is improved from 10.29% to 13.01% after modification. Furthermore, the stability of the device has been improved. This study provides a strategy for developing highly efficient and stable C-PSCs.

Unlocking Voltage Potentials of Mixed‐Halide Perovskite Solar Cells via Phase Segregation Suppression

AbstractWide bandgap (Eg) mixed‐halide perovskite has attracted much attention for applications in photovoltaic devices. However, devices featuring this type of perovskite are often subject to a large voltage deficit due to the occurrence of phase segregation, which limits the relevant devices’ access to high performances. Here, the correlation of the phase segregation and voltage losses for wide‐Eg mixed‐halide perovskite solar cells (PSCs) is clarified by experiments and simulations. Taking 1.67 eV Eg mixed‐halide perovskite as an example, it is confirmed experimentally that the control devices produce a poor physical morphology, a locally widened Eg, and an inferior electrical response. By suppressing the phase segregation, the open‐circuit voltage (Voc) can be boosted from 1.15 to 1.20 V, which is a high value for the 1.67 eV Eg mixed‐halide PSCs. An electrical simulation of phase segregation reveals that the performance degeneration can be attributed to the bulk recombination due to the energy level mismatch of the varied Egs. Moreover, a theoretical perspective is produced to expatiate on the strategies for the high Voc of wide‐Eg PSCs. This study brings deep guidance to unlock the potential for high‐performance mix‐halide PSCs.

Efficient and Stable Carbon‐Based CsPbIBr2 Perovskite Solar Cells by 4‐Aminomethyltetrahydropyran Acetate Modification

AbstractInorganic cesium lead halide perovskite solar cells have attracted widespread attention owing to their excellent stability relative to organic–inorganic solar cells. However, all‐inorganic perovskite solar cells without hole transport layers and using carbon layers as electrodes have serious energy level mismatch problems. To overcome this problem, here, the CsPbIBr2 surface is treated with 4‐aminomethyltetrahydropyran acetate to form a gradient energy band on the CsPbIBr2 perovskite/carbon interface. As a result, the hole extraction efficiency is successfully improved, and the morphology and crystallization of the perovskite layer are also improved. Moreover, the nonradiative recombination inside the perovskite and the charge recombination at the interface are effectively inhibited. Therefore, the power conversion efficiency of CsPbIBr2 solar cell is enhanced to 10.12%, and the high photovoltage of 1.32 V is obtained under one solar illumination, which are both higher than the pristine one (7.79%, 1.23V, respectively).

Low Temperature Producing Copper‐Doped Gallium Oxide as Hole Transport Layers of Perovskite Solar Cells Enhanced by Impurity Levels

In inverted perovskite solar cells (PSCs), metal oxides become kind of promising hole transport layers for their facile synthesis and low cost. For conventional hole transport materials, the valence band match between metal oxides and perovskite layers is usually necessary for the hole extraction process. Ga2O3 is an emerging semiconductor material with ultrawide bandgap, but a significant energy level mismatch exists at Ga2O3/perovskite interfaces. In this work, Cu‐doped Ga2O3 (Ga2O3:Cu) nanocrystals are synthesized by the hydrothermal method and used as the hole transport material of inverted PSCs for the first time. It is found that Cu dopants can substantially improve the performance of Ga2O3 layers, and the efficiency of PSCs is increased from 7.6% to 19.5%. This improvement can be attributed to the additional hole transport channels from impurity levels of Cu dopants, which exactly match with the valence band of perovskite layers. As a consequence, Ga2O3:Cu layers can effectively extract holes and inhibit the recombination in perovskite layers. This work also provides an alternative route for the design of hole transport materials.

The interface modified by CsPbBr3 quantum dots for hole transport layer-free perovskite solar cell

The serious energy level mismatch between the perovskite layer and the collecting electrode in direct contact is the main reason limiting the efficiency improvement of perovskite solar cell without transport layer. Here, zero-dimensional CsPbBr3 quantum dots with tunable energy levels is used to modify the interface of the hole transport layer free perovskite solar cell, adjust the level distribution of the interface, promote the effective extraction of holes and suppress the injection of electrons, and successfully improve the photoelectric conversion efficiency of the hole transport layer free perovskite solar cell by 1.25 times.

Interfaces and Interfacial Layers in Inorganic Perovskite Solar Cells

Owing to their superior thermal stability, metal halide inorganic perovskite materials continue to attract interest for photovoltaics applications. The highest reported power conversion efficiency (PCE) for solar cells based on inorganic perovskites is over 20 %. As this PCE corresponds to 73 % of the theoretical limit, there remains more room for further improving the device PCEs than for improving organic-inorganic hybrid perovskite solar cells (PSCs). The main loss is in the photovoltage, which is limited by interfaces in terms of non-radiative recombination caused by traps and energy-level mismatch. Furthermore, inefficient charge extraction at interfacial contacts reduces the photocurrent and fill factor. This Minireview summarizes the recent developments in the fundamental understanding of how the interfaces and interfacial layers influence the performance of solar cells based on inorganic perovskite absorbers. An outlook for the development of highly efficient and stable inorganic PSCs from the interface point of view is also given.

Chiral cation promoted interfacial charge extraction for efficient tin-based perovskite solar cells

Pb-free Sn-based perovskite solar cells (PSCs) have recently made inspiring progress, and power conversion efficiency (PCE) of 14.8% has been achieved. However, due to the energy-level mismatch and poor interfacial contact between commonly used hole transport layer (i.e., poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate), PEDOT:PSS) and FASnI3 film, it is still challenging to effectively extract holes at the interface. Owing to the p-type nature of Sn-based perovskites, the efficient hole extraction is of particular significance to improve the PCE of their solar cells. In this work, for the first time, the role of chiral cations, α-methylbenzylamine (S-/R-/rac-MBA), in promoting hole transportation of FASnI3-based PSCs is demonstrated. The introduction of MBAs is found to form 2D/3D film with low-dimensional structures locating at PEDOT:PSS/FASnI3 interface, which facilitates the energy level alignment and efficient charge transfer at the interface. Importantly, chiral-induced spin selectivity (CISS) effect of R-MBA2SnI4 induced by chiral R-MBA cation is found to further assist the specific interfacial transport of accumulated holes. As a result, R-MBA-based PSCs achieve decent PCE of 10.73% with much suppressed hysteresis and enhanced device stability. This work opens up a new strategy to efficiently promote the interfacial extraction of accumulated charges in working PSCs.

Preferential vertically oriented nanopillar perovskite induced by poly(9-vinylcarbazole) field-effect transistor

Organic-inorganic hybrid perovskite could potentially be used to create field-effect transistors (FETs) with high field-effect mobility. However, the energy level mismatch at the deep valence band maximum perovskite-contact junction and morphological defects greatly limit the charge transport in the thin film. In this work, we demonstrated charge injection can be improved by introducing Nafion as a surface modifier on top of the Indium tin oxide. Incorporating poly (9-vinylcarbazole) PVK into a quasi-one-dimensional precursor solution induced preferential vertically orientated nanopillars as revealed by synchrotron-based two-dimensional grazing incident X-ray diffraction. This simultaneously reduced the grain boundaries and improved pin-hole free films. As a result, maximum hole mobility of 0.012 cm2/Vs was achieved with a reduction in the hysteresis. Our work demonstrated the dependence of FETs performance on the injection barrier and perovskite nanopillar microstructure.

Ultrafast Study of Exciton Transfer in Sb(III)-Doped Two-Dimensional [NH3(CH2)4NH3]CdBr4 Perovskite.

Antimony-based metal halide hybrids have attracted enormous attention due to the stereoactive 5s2 electron pair that drives intense triplet broadband emission. However, energy/charge transfer has been rarely achieved for Sb3+-doped materials. Herein, Sb3+ ions are homogeneously doped into 2D [NH3(CH2)4NH3]CdBr4 perovskite (Cd-PVK) using a wet-chemical method. Compared to the weak singlet exciton emission of Cd-PVK at 380 nm, 0.01% Sb3+-doped Cd-PVK exhibits intense triplet emission located at 640 nm with a near-unity quantum yield. Further increasing the doping concentration of Sb3+ completely quenches singlet exciton emission of Cd-PVK, concurrently with enhanced Sb3+ triplet emission. Delayed luminescence and femtosecond-transient absorption studies suggest that Sb3+ emission originates from exciton transfer (ET) from Cd-PVK host to Sb3+ dopant, while such ET cannot occur with Pb2+-doped Cd-PVK because of the mismatch of energy levels. In addition, density function theory calculations indicate that the introduced Sb3+ likely replace the Cd2+ ions along with the deprotonation of butanediammonium for charge balance, instead of generating Cd2+ vacancies. This work provides a deeper understanding of the ET of Sb3+-doped Cd-PVK and suggests an effective strategy to achieve efficient triplet Sb3+ emission beyond 0D Cl-based hybrids.

A double perovskite participation for promoting stability and performance of Carbon-Based CsPbI2Br perovskite solar cells

All-inorganic perovskite materials (Typically: CsPbI2Br) have attracted enormous attention due to their illustrious thermal stability and appropriate bandgap, and their use in perovskite solar cells (PSCs) has been extensively investigated. However, the inevitable defects of the perovskite layer, energy level mismatch between perovskite and carbon electrodes, and the phase instability of CsPbI2Br limit the power conversion efficiency (PCE) and stability of carbon-based CsPbI2Br PSCs. Herein, we demonstrate a simple and effective strategy for regulating energy level, inhibiting carrier recombination, and delaying the degradation of perovskite by modifying the surface of CsPbI2Br with a new type of 2D perovskite Cs2PtI6. The carbon-based CsPbI2Br PSCs achieve a higher PCE (13.69 %) than the control device (11.10 %). The excellent matching of the energy level and suppression of charge carrier recombination should be responsible for the improvement in efficiency. Furthermore, the excellent hydrophobic performance of Cs2PtI6 enhances the moisture resistance of the device. This study provides a potential strategy for improving the performance and stability of all-inorganic CsPbI2Br PSCs.

Highly Enhanced Efficiency of Planar Perovskite Solar Cells by an Electron Transport Layer Using Phytic Acid–Complexed SnO2 Colloids

SnO2 aqueous colloids as electron transport layers (ETLs) have been widely employed in planar perovskite solar cells (PSCs). However, the surface defects and energy level mismatch at the SnO2 ETL/perovskite interface are still great challenges for the power conversion efficiency (PCE) improvement. Herein, a natural and nontoxic phytic acid (PA) compound is introduced into the SnO2 aqueous colloids to prepare the ETL to depress its defects, and systematically study the influence of different PA complexation on the photovoltaic performance of PSCs. The results demonstrate that PA complexation can assemble unique coordination complexes between PA and SnO2 nanocrystals (NCs) in a new bonding of SnOP, which can passivate SnO2 inherent surface defects and tune the electronic properties of SnO2 ETLs. PA complexation can significantly disaggregate the SnO2 oligomers and reduce the cluster size distribution from 98.37 to 15.87 nm. Meanwhile, the reduction of surface trap states inhibits the potential barriers, thus the electrical conductivity is about two times as high as compared with the pristine SnO2 ETLs. Consequently, a high PCE of 21.43% in PA‐SnO2‐based PSCs is obtained, which presents an improvement of 10.9% over that of the pristine SnO2‐based PSCs.

Enlarged temperature lift of hybrid compression-absorption heat transformer via deep thermal coupling

The energy level mismatch between heat sources and industry users has posed a huge barrier for the wide application of local waste heat recovery, which cannot be efficiently addressed by traditional options due to the limited temperature lift. To fill this gap, a hybrid heat transformer is proposed to achieve large temperature lift via deep thermal coupling between compression and absorption sub-cycles. Firstly, simulation shows that 42.1 kW heat output (at 100 °C) is provided with the costs of 20.0 kW electricity and 67.4 kW waste heat (at 45 °C), resulting in a COP of 2.15 and a large temperature lift of 55 °C. Secondly, an experimental prototype was established for performance validation, which stably upgraded the waste heat from 47–51 °C to 99–102 °C with an overall COP of 1.81. Further investigation shows that the proposed system is quite flexible with waste heat source temperatures of 30–60 °C and output temperatures of 90–115 °C. Such an effective heat transformer with large temperature lift could be promoted for the efficient utilization of low-grade waste heat, and contribute to the industrial decarbonization.

Modification of Energy Level Alignment for Boosting Carbon‐Based CsPbI2Br Solar Cells with 14% Certified Efficiency

AbstractHole transfer material (HTM)‐free, carbon‐based all‐inorganic perovskite solar cells (C‐PSCs) are promising alternatives to conventional organic–inorganic hybrid PSCs in addressing thermal and moisture instability issues. However, the energy level mismatch between the inorganic perovskite and carbon electrode coupled, together with the incapability of the carbon electrode to reflect incident light for reabsorption, limits the power conversion efficiency (PCE) of C‐PSCs. To address these issues, herein, a new strategy of a hexyltrimethylammonium bromide (HTAB)‐modified CsPbI2Br perovskite surface is devised to reduce this energy offset from 0.70 to 0.32 eV and increase the built‐in potential by 70 mV for the final devices. Additionally, a CsPbI2Br perovskite film with a thickness of up to 800 nm is realized via a hot‐flow‐assisted spin coating approach in an ambient atmosphere with humidity of less than 80%. Reduced energy offset coupled with suppressed charge recombination and thick perovskite layer boosts the champion PCE of CsPbI2Br C‐PSCs to 14.3% (Jsc = 14.1 mA cm−2, Voc = 1.26 V, and fill factor = 0.806), and the average PCE to 13.9% under one sun illumination. A new certified efficiency record of 14.0% is obtained for HTM‐free inorganic C‐PSCs. Meanwhile, the moisture‐resistant barrier from the alkyl chain in HTAB improves the stability of the final devices.

Energy grade splitting of hot water via a double effect absorption heat transformer

Energy level mismatch between waste heat and energy users poses huge barrier for local waste heat recovery. To tackle this challenge, an energy grade splitting strategy of hot water via absorption heat transformer is proposed. In this strategy, the hot water is separated into two branches. An absorption heat transformer extracts waste heat from the colder branch, and delivers heat output to increase the temperature of hotter branch. This process could deliver high temperature output and decrease the temperature of waste heat simultaneously, which meets the local waste heat recovery demand. Both experimental and modeling researches are carried out to investigate this strategy. Firstly, double effect LiBr-water absorption heat transformer is adopted for performance enhancement, and experimental investigation was carried out. Testing results showed that 391.4 kW heat output and COP of 0.618 were achieved, under colder branch temperature of 149.7 → 128.1 °C and hotter branch temperature of 151.0 → 128.1 °C. Secondly, modeling framework was built and used to evaluate the energy grade splitting performance under different conditions. Results showed that the proposed energy grade splitting strategy is effective under waste heat source temperatures of 130.0–160.0 °C, temperature lift of 5.0–20.0 °C, mass split ratio of 0.10–1.60 and temperature split ratio of 2.00–20.00. Such an effective and flexible strategy could further be promoted to other scenarios with different heat conversion technologies, and contribute to the wide application of local waste heat recovery.