Introducing Porphyrin Units by Random Copolymerization Into NDI-Based Acceptor for All Polymer Solar Cells

Abstract

Naphthalene diimide (NDI)-based polymer N2200 is a promising organic polymer acceptor for all-polymer solar cells (all-PSCs), but its inherent shortcomings like poor extinction coefficient and strong aggregation limit further performance optimization of all-PSCs. Here, a series of random copolymers, PNDI-Px, were designed and synthesized by introducing porphyrin unit into NDI-based polymer as acceptors for all-PSCs. These random copolymers show a higher absorption coefficient and raised the lowest unoccupied molecular orbital (LUMO) energy levels compared to N2200. The crystallinity can also be fine-tuned by regulation of the content of porphyrin unit. The random copolymers are matched with polymer donor PBDB-T for the application in all-polymer solar cells. The best power conversion efficiency (PCE) of these PNDI-Px-based devices is 5.93%, ascribed to the overall enhanced device parameters compared with the N2200-based device. These results indicate that introducing porphyrin unit into polymer is a useful way to fine-tune the photoelectric performance for efficient all-PSCs.

n-Type polymer electron acceptors for organic solar cells

“…Researchers have developed numerous acceptor materials based on NDI by adjusting the conjugated main chain, 52,53 flexible side chains 54,55 and ternary random copolymerization. [56][57][58] Kim et al 52 designed and synthesized two new polymer acceptors (PNDITCVT-HD and PNDITCVT-OD, Fig. 2e) by incorporating electron-withdrawing cyanovinylene groups into the backbone of N2200.…”

“…Researchers have developed numerous acceptor materials based on NDI by adjusting the conjugated main chain, 52,53 flexible side chains 54,55 and ternary random copolymerization. 56–58…”

“…3j) increased the PCE of the all-POSCs (8.5%). Chen and co-workers 58 introduced porphyrin unit in an NDI-based polymer and obtained a series of random copolymers, PNDI-P x (Fig. 2i).…”

Enhanced non-linear optical properties of porphyrin-based polymers covalently functionalized with graphite phase carbon nitride

“…Meanwhile, due to the structural adjustability, unique electronic and photophysical properties of porphyrins, porphyrins have broad application in various areas and good prospects ( Zhang et al, 2018 ; Chen et al, 2020 ; Asghar et al, 2021 ; Liu and Cheng, 2021 ). Particularly, the NLO performance of porphyrins could be improved by the flexible modification of peripheral substituents or the hybridization with other materials ( Zawadzka et al, 2013 ; Woller et al, 2016 ; Hu et al, 2018 ; Biswal et al, 2019 ; Samal et al, 2019 ; Liu J. L. et al, 2020 ; Liu Z. et al, 2020 ; Liu and Cheng, 2021 ; Ramasamy et al, 2022 ). However, previous research indicated the self-aggregate behavior of porphyrins could lead to the formation of large macro-scale and fractal structures, causing a negative impact in the development of NLO devices in practice ( Kalachyova et al, 2014 ).…”

Thiophene with Oligoethylene Oxide Side Chain Enables Random Terpolymer Acceptor to Achieve Efficient All‐Polymer Solar Cells

“…[7][8][9][10][11] Compared with small molecule materials, polymer materials have better intrinsic stability, higher mechanical stability and more suitable for printed fabrication, therefore, allpolymer solar cells (all-PSCs) consisting of p-type polymer donors and n-type polymer acceptors have attracted more and more attention and research from different research groups. [12][13][14][15][16] Thanks to the tremendous efforts, such as optimization of molecular weight, [17,18] random copolymerization, [19][20][21] and optimization of deposition techniques, [22,23] many high efficiency devices have been widely reported, and the optimal PCE of all-PSCs has been improved to more than 15 %. [24][25][26][27] Nevertheless, the photovoltaic performance of all-PSCs still lags behind that of the current state-of-theart PSCs based on non-fullerene fused-ring electron acceptors.…”