Three birds with one stone: Nitrilotriacetic acid interface anchoring helps prepare efficient and stable perovskite solar cells

Abstract

Electron transport layer (ETL) plays an important role in perovskite solar cells (PSCs). In this paper, a stable and cheap metal chelating agent, subnitrotriacetic acid (NTA), was used to modify SnO2 ETL in two ways:1) By incorporating NTA into SnO2 colloidal dispersion, the oxygen vacancy causing charge recombination was greatly reduced, and the recombination of psc was reduced by reducing the introduction of surface Ovs, 2) Spin-coating NTA at the SnO2/perovskite interface not only manages a large number of oxygen vacancies generated by high-temperature annealing, but also interacts with the unpaired Pb2+ in the perovskite absorption layer by interface modification of the CO bond in NTA, passivates the surface of the perovskite layer, inhibits ion migration, stabilize the perovskite structure, and avoid its collapse, while significantly reducing the defect state density. By inhibiting the shallow interface trap and reducing the non-radiative recombination, efficient and stable perovskite solar cells were prepared. Under the condition of relative humidity greater than 40 % (RH), the efficiency of perovskite solar cells prepared by interface-anchored NTA was increased to 22.6 %, and the stability was significantly enhanced.