The Energy‐Alignment Engineering in Polytriphenylamines‐Based Hole Transport Polymers Realizes Low Energy Loss and High Efficiency for All‐Inorganic Perovskite Solar Cells

Abstract

The energy loss ( E loss ) control via interfacial engineering is a significant indispensible methodology to realize high‐performance all‐inorganic perovskite solar cells (PVSCs). Herein, three novel polytriphenylamine‐based polymer derivatives (H‐Z1, H‐Z2, and H‐Z3) are synthesized, and the energy levels of these polymers are tuned feasibly through introducing the electron‐withdrawing group of trifluoromethyl in the triphenylamine (TPA) unit. These very deep HOMO energy levels are very beneficial for improving the open‐circuit voltages (V oc s) in PVSCs with the potentially decreased E loss s. Due to the gradual deepening of HOMO energy levels from H‐Z1, H‐Z2 to H‐Z3, the V oc s are elevated from 1.23, 1.28 to 1.30 V, respectively, where the E loss s are decreased from 0.69, 0.64, to 0.62 eV for H‐Z1, H‐Z2, and H‐Z3, respectively. Interestingly, both of the H‐Z1‐ and H‐Z2‐based devices show the highest PCEs, over 14%, in all‐inorganic PVSCs, which are effectively comparable to the results of reference device using Spiro‐OMeTAD as HTL. Thus, through the efficient atomic engineering and chemical modification in corresponding p‐typed polymers, excellent hole transport polymers are achieved for high‐performance and stable PVSCs with very low E loss .