Balancing the Energy levels and Charge Mobility of the Conjugated Polymer PM6 by a Third Component to Enable Efficient Organic Solar Cells

Abstract

AbstractThe notable wide bandgap conjugated polymer (WB‐CP) PM6 was optimized by introducing the third component of 4,8‐bis(tri‐iso‐propylsilicylethynyl)benzo[1,2‐b;4,5‐b’]dithiophene (BDT‐TIPS). With the increase of the BDT‐TIPS contents in the WB‐CPs, the maximal absorption peaks and on‐set‐band gap wavelengths of the WB‐CPs, are gradually blue‐shifted, alongside the successive deepening of the highest occupied molecular orbital (HOMO) from −5.54 eV to −5.68 eV. The more efficient OSCs with PCEs of 16.38 % were achieved in the OSCs from PM6‐TIPS5 paired with Y6 in contrast to that of 15.76 % for PM6 : Y6 based OSCs under AM1.5 sun stimulation (100 mA/cm2). Besides that, the investigations of the charge transporting, exciton dissociation and the recombination characteristics etc., were implemented and sugessted the improvement of the PCEs of PM6‐TIPS5 based OSCs was mainly ascribed to the subtly balancing of the HOMO energy levels and charge mobility of the PM6 by optimization of the feed ratio of the BDT‐TIPS.