A Non‐Conjugated Polymer Acceptor for Efficient and Thermally Stable All‐Polymer Solar Cells

Abstract

A non-conjugated polymer acceptor PF1-TS4 was firstly synthesized by embedding a thioalkyl segment in the mainchain, which shows excellent photophysical properties on par with a fully conjugated polymer, with a low optical band gap of 1.58 eV and a high absorption coefficient > 10 5 cm À1 , a high LUMO level of À3.89 eV, and suitable crystallinity. Matched with the polymer donor PM6, the PF1-TS4-based all-PSC achieved a power conversion efficiency (PCE) of 8.63 %, which is % 45 % higher than that of a device based on the small molecule acceptor counterpart IDIC16. Moreover, the PF1-TS4-based all-PSC has good thermal stability with % 70 % of its initial PCE retained after being stored at 85 8C for 180 h, while the IDIC16-based device only retained % 50 % of its initial PCE when stored at 85 8C for only 18 h. Our work provides a new strategy to develop efficient polymer acceptor materials by linkage of conjugated units with non-conjugated thioalkyl segments.

A Narrow‐Bandgap n‐Type Polymer with an Acceptor–Acceptor Backbone Enabling Efficient All‐Polymer Solar Cells

“…[ 7–12 ] Among various OSCs, all‐polymer solar cells (all‐PSCs) employing conjugated polymers as both the electron donors and acceptors, have recently attracted great attention because of some unique advantages including superior stability and mechanical robustness. [ 13–20 ] However, only a few polymer acceptors can yield PCEs over 8% till now (see Figure S1 and Table S1, Supporting Information) due to the scarcity of highly electron‐deficient building blocks. For instance, classical naphthalene diimide and perylene diimide‐based donor–acceptor (D–A)‐type polymer acceptors (see Figure S2a, Supporting Information) suffer from poor absorption coefficient in the long‐wavelength region and (or) the localized lowest unoccupied molecular orbital (LUMO), which limits the short‐circuit currents density ( J sc ) and V oc , together with relatively large E loss,nr , leading to much lower PCEs than those of FREA‐based OSCs.…”

Configurational Isomers Induced Significant Difference in All‐Polymer Solar Cells

“…It should be mentioned that polymers based on this strategy will have the properties of both SMAs and polymer acceptors. Accordingly, a series of PSMAs based on IDIC, [ 22–26 ] ITIC, [ 27–29 ] and BTIC [ 5–9,30,31 ] were synthesized, and a remarkable advance in all‐polymer solar cells was achieved.…”

Asymmetric Isomer Effects in Benzo[c ][1,2,5]thiadiazole‐Fused Nonacyclic Acceptors: Dielectric Constant and Molecular Crystallinity Control for Significant Photovoltaic Performance Enhancement

“…[ 1–10 ] Since the advent of non‐fullerene small‐molecule acceptor (SMA) ITIC in 2015, [ 11 ] a rapidly improved OSC performance has been witnessed over the past five years with the highest power conversion efficiencies (PCEs) exceeding 18%. [ 12–25 ] These remarkable advances are stemmed from multiple structure modifications of SMAs including side‐chains, electron‐rich cores and electron‐deficient terminal groups, enabling precise control over their optical properties, energy levels and crystallization/aggregation behaviors. [ 12–15,26–39 ]…”

“…[1][2][3][4][5][6][7][8][9][10] Since the advent of non-fullerene smallmolecule acceptor (SMA) ITIC in 2015, [11] a rapidly improved OSC performance has been witnessed over the past five years with the highest power conversion efficiencies (PCEs) exceeding 18%. [12][13][14][15][16][17][18][19][20][21][22][23][24][25] These remarkable advances are stemmed from multiple structure modifications of SMAs including side-chains, electron-rich cores and electron-deficient terminal groups, enabling precise control over their optical properties, energy levels and crystallization/aggregation behaviors. [12][13][14][15][26][27][28][29][30][31][32][33][34][35][36][37][38][39] The evolution of material development in OSCs in the past few years has established a huge library of structure-performance relationship for the design of…”