Efficient ternary blend all-polymer solar cells with a polythiophene derivative as a hole-cascade material

Efficient ternary all polymer solar cells (all-PSCs) based on PTB7-Th : PBDD-ff4T : N2200 were reported, where PTB7-Th and PBDD-ff4T were two polymer donors and N2200 was a polymer acceptor. The all-PSCs showed an optimized PCE of up to 7.2% which is superior to those of the binary all-PSCs based on PTB7-Th : N2200 and PBDD-ff4T : N2200 .