Effect of Annealing Process on CH₃NH₃PbI_3-XCl_X Film Morphology of Planar Heterojunction Perovskite Solar Cells with Optimal Compact TiO₂ Layer

Abstract

The morphology of compact TiO 2 film used as an electron-selective layer and perovskite film used as a light absorption layer in planar perovskite solar cells has a significant influence on the photovoltaic performance of the devices. In this paper, the spin coating speed of the compact TiO 2 is investigated in order to get a high-quality film and the compact TiO 2 film exhibits pinhole-and crack-free films treated by 2000 rpm for 60 s. Furthermore, the effect of annealing process, including annealing temperature and annealing program, on CH 3 NH 3 PbI 3-X Cl X film morphology is studied. At the optimal annealing temperature of 100°C, the CH 3 NH 3 PbI 3-X Cl X morphology fabricated by multistep slow annealing method has smaller grain boundaries and holes than that prepared by one-step direct annealing method, which results in the reduction of grain boundary recombination and the increase of Voc. With all optimal procedures, a planar fluorine-doped tin oxide (FTO) substrate/compact TiO 2 / CH 3 NH 3 PbI 3-X Cl X /Spiro-MeOTAD/Au cell is prepared for an active area of 0.1 cm 2 . It has achieved a power conversion efficiency (PCE) of 14.64%, which is 80.3% higher than the reference cell (8.12% PCE) without optimal perovskite layer. We anticipate that the annealing process with optimal compact TiO 2 layer would possibly become a promising method for future industrialization of planar perovskite solar cells.

Influence of Film Thickness on the Electronic Band Structure and Optical Properties of P–I–N CH3NH3PbI3−xClx Perovskite Solar Cells

“…[7] Planar heterojunction P-I-N and N-I-P PSCs are promising structures compared with their counterpart mesoporous PSCs because of the high annealing temperature and additional processing difficulties required for preparing mesoporous TiO 2 . [8] Among different methylammonium lead halide perovskite, such as CH 3 NH 3 PbI 3 , CH 3 NH 3 PbBr 3 , and CH 3 NH 3 PbI 3Àx Cl x , the CH 3 NH 3 PbI 3Àx Cl x structure is more suitable for planar heterojunction PSCs, owing to its remarkable properties such as long diffusion lengths (L D ) for both holes and electrons [2,9,10] and an appropriate bandgap. [11] The L D of CH 3 NH 3 PbI 3 is about 100 nm; [5] however, it can be increased up to 1 μm upon the addition of chlorine (Cl) to form the CH 3 NH 3 PbI 3Àx Cl x structure.…”

Numerical investigation of graphene and 2D‐MoS 2 facilitated perovskite/silicon “p‐i‐n” structure for solar cell application

“…Moreover, it has been reported that ultrathin gold (Au) contact has better electrical conductivity as well as optical reflectance‐scattering to preserve the performance of the cell 56 . Chen et al 57 have also demonstrated the application of Au as a back contact in CH 3 NH 3 PbI 3−x Cl x ‐based solar cells. Due to these advantages of cSi and Au, we proposed these as an HTL and back contact in the proposed structures.…”

Fabrication of Affordable and Sustainable Solar Cells Using NiO/TiO2 P-N Heterojunction

“…Heterojunctions are known to be the most competitive method of solar cell fabrication on account of being the simplest [36]. A P-N junction is created when P-type (NiO) and N-type (TiO 2 ) semiconductor materials are placed in contact with one another.…”