The power conversion efficiency of lead halide perovskite solar cells has been elevated to 25.2%. However, the toxicity of lead and the complex fabrication process of those cells considerably hinder the commercial application of such solar cells. Therefore, lead-free solar cells with comparable power conversion efficiency with a much lower environmental impact have recently attracted enormous attention in both academia and industry. This paper presents a theoretical study to assess the energy conversion capacity of lead-free perovskite solar cells with MASnI3 perovskite as its absorber layer using solar cell capacitance simulator (SCAPS). In particular, the effects of materials of the perovskite solar cells’ electron transport layers (ETLs) and hole transport layers (HTLs) on their energy conversion performance are elaborated. Our results show that Cd0.5Zn0.5S and MASnBr3 are the most suitable materials for ETL and HTL, respectively. It is also found from that the solar cell performance can be further enhanced through optimizing the thickness and defect density of its absorber layer. Moreover, the effects of defect densities in interface layers are investigated. In addition, the effects of ETL and HTL doping densities as well as influences of the back-contact work function and operating temperature of the tin-based perovskite solar cells are discussed. Finally, a glass substrate/FTO/Cd0.5Zn0.5S (ETL)/MASnI3/MASnBr3 (HTL)/back-contact solar cell with a power conversion efficiency of 23.86% is recommended for further optimization.

Self-powered photodetectors (PDs) with inorganic lead halide perovskites hold multiple traits of high sensitivity, fast response, independence from external power supply, and excellent sustainability and stability, thus holding a great promise for practical applications. However, they generally contain high-temperature-processed electron-transporting layers (ETLs) and high-cost, unstable hole-transporting layers (HTLs) coupled with noble metal electrodes, which bring significant obstacles of production cost and stability for their potential commercialization. Herein, we demonstrate the building of high-performance HTL/ETL-free, self-powered CsPbIBr2 PD with simplified architecture of fluorine-doped tin oxide (FTO)/CsPbIBr2/carbon upon interfacial modification by polyethyleneimine (PEI). The optimized PD yields a dark current of 2.03 × 10–9 A, peak responsivity (R) of 0.32 A/W, maximum specific detectivity (D*) of 3.74 × 1012 Jones, and response time of 1.21 μs. These figures of merit are far beyond those of the one prepared without PEI modification and even the PD containing TiO2 ETL. Hence, our work suggests a highly feasible route to develop self-powered PDs with significantly simplified fabrication and a reduced production cost.

In this work, the effects of the SiO x interface layer grown by exposure in air on the performance of planar hybrid n-Si/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solar cells are investigated. Compared to the cell with a hydrogen-terminated Si surface, the cell with an oxygen-terminated Si surface reveals improved characteristics in power conversion efficiency, increased from 10.44% to 13.31%. By introducing the SiO x , the wettability of the Si surface can be improved, allowing an effective spread of the PEDOT:PSS solution and thus a good contact between the PEDOT:PSS film and Si. More importantly, it can change the polarity of the Si surface from a negative dipole to a positive dipole, owing to the introduction of the SiO x interface. The Si energy band will bend up and give rise to a favorable band alignment between Si and PEDOT:PSS to promote carrier separation. These results could be potentially employed to further development of this simple, low-cost heterojunction solar cell.

The inorganic perovskite has a better stability than the hybrid halide perovskite, and at the same time it has the potential to achieve an excellent photoelectric performance as the organic-inorganic hybrid halide perovskite. Thus, the pursuit of a low-cost and high-performance inorganic perovskite solar cell (PSC) is becoming the research hot point in the research field of perovskite devices. In setting out to build vacuum-free and carbon-based all-inorganic PSCs with the traits of simple fabrication and low cost, we propose the ones with a simplified vertical structure of FTO/CsPbIBr2/carbon upon interfacial modification with PEI species. In this structure, both the electron-transporting-layer and hole-transporting-layer are abandoned, and the noble metal is also replaced by the carbon paste. At the same time, FTO is modified by PEI, which brings dipoles to decrease the work function of FTO. Through our measurements, the carrier recombination has been partially suppressed, and the performance of champion PSCs has far exceeded the control devices without PEI modification, which yields a power conversion efficiency of 4.9% with an open circuit voltage of 0.9 V and a fill factor of 50.4%. Our work contributes significantly to give an available method to explore charge-transporting-layer-free, low-cost, and high-performance PSCs.

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