Fully Doctor-bladed efficient perovskite solar cells in ambient condition via composition engineering

Abstract It is very meaningful to develop large-scale, low-cost technology for fabricating efficient perovskite solar cells (PSCs) to accelerate their commercialization. Doctor-blading is one of important scalable technologies for processing PSCs, but the power conversion efficiencies (PCEs) of fully doctor-bladed PSCs, including electron transport layer, perovskite layer and hole transport layer, are still lag far behind the PSCs fabricated via conventional spin-coating technology, especially fabricated in ambient condition. Herein, highly efficient planar heterojunction PSCs with a structure of ITO/SnO2/FAxMA(1-x)PbIyBr(3-y)/Spiro-OMeTAD/Ag are achieved by fully doctor-blading technique in ambient condition, in which high-quality perovskite films with low trap-density are fabricated via two-step sequential deposition with a low temperature process by simultaneously introducing composition engineering and additive-doping technology. Organic cation is added into the PbI2 precursor to reduce the uneven distribution of nucleation sites in the perovskite films during doctor-blading process and promote the uniform growth of perovskite grain. Moreover, 2,3,5,6-tetrafluoro-7,7,8,8-tetra-cyanoquinodimethane (F4-TCNQ) acted as the doping additive is employed into perovskite, resulting in healing the perovskite grain boundary and reducing trap-density accordingly. As a result, the doctor-bladed PSCs fabricated in ambient condition exhibit the champion PCE of 18% and a stabilized efficiency of 17.7%. Furthermore, PSCs fabricated via fully doctor-blading in ambient condition achieve the PCE of 17.0% with negligible hysteresis. This work provides an important strategy for scalable fabrication of efficient PSCs in ambient condition and potentially accelerates the commercialization.