Efficient p-n Heterojunction Perovskite Solar Cell without a Redundant Electron Transport Layer and Interface Engineering

We report an electron transport layer-free perovskite solar cell (PSC) without interface engineering, whose key is a p-n heterojunction consisting of ITO/n-type FA(0.9)Cs(0.1)PbI(3-x)Cl(x)/p-type spiro-MeOTAD/Ag. The naturally matched energy levels between FA(0.9)Cs(0.1)PbI(3-x)Cl(x) and ITO make interface engineering unnecessary. The FA(0.9)Cs(0.1)PbI(3-x)Cl(x) film has a wide antisolvent processing window, favoring large-area production. The self-seeding growth method regulates the energy levels and work function of the FA(0.9)Cs(0.1)PbI(3-x)Cl(x) film via modulating the shape and distribution of residual PbI2. Interface band bending is confirmed by double-side photoluminescence (PL) measurement. Reduced PL is introduced for unambiguous charge transfer analysis without interference caused by different absorbance. Accordingly, enhanced ITO/perovskite interface energy level alignment and device performance (efficiency of 17.48% and V-oc of 1.02 V) are demonstrated. Such simplified but efficient PSCs featuring a wide antisolvent processing window have great potential in practical applications.

Automated summary

This study presents an electron transport layer-free perovskite solar cell without interface engineering, utilizing a p-n heterojunction and self-seeding growth method to achieve enhanced efficiency and wide production window. Improved device performance and energy level alignment demonstrate the great potential of this simplified yet efficient PSC for practical applications.