Facile RbBr interface modification improves perovskite solar cell efficiency

Abstract High-performance hybrid perovskite solar cell (PSC) is an emerging generation of energy material by virtue of its excellent properties such as wide light absorption range, large electron diffusion length, and small exciting energy. However, to date, methods of perovskite deposition generally do not offer desired film coverage, resulting in the direct interfacial contact, which seriously deteriorates the photovoltaic performance of devices. To improve the interfacial functions of the perovskite layer (PL)/electron transport layer (ETL) of the PSC devices, rubidium bromide (RbBr) is applied as a facile interfacial modifier. It is sandwiched between ETL tin oxide (SnO2) and PL [Cs0.05(MA0.17FA0.83)0.95Pb(I0·83Br0.17)3] to a fabricate a planar PSC. The RbBr modification of the PSC fluorine-doped tin oxide/SnO2/(RbBr)/PL/spiro-OMeTAD/Au (2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spiro-bifluorene) can reduce the energy barrier at the ETL/PL interface, improve the electronic contact between PL and ETL, and accelerate the electron extraction process. The RbBr modification thus leads to a higher power conversion efficiency of 18.29% for the PSC, as compared with 16.03% without RbBr modification. The facile RbBr modification procedure and significant performance advancement pave the way for future energy studies.