Highly Efficient Parallel-Like Ternary Organic Solar Cells

Abstract

Ternary bulk heterojunction (BHJ) blends have been demonstrated as a promising approach to increase the power conversion efficiencies (PCEs) of organic solar cells. Currently, most studies of ternary organic solar cells are based on blends of two donors and one acceptor, because of the limitation in acceptor materials. Here, we report that high-performance ternary solar cells have been fabricated with a wide-bandgap polymer donor (PDBT-T1) and two acceptor materials, phenyl-C70-butyric acid methyl ester (PC 70 BM), and nonfullerene acceptor (ITIC-Th). The addition of ITIC-Th into the BHJ blends dramatically increases the light absorption. Consequently, the champion ternary solar cell shows a high PCE of ∼10.5%, with an open-circuit voltage (V oc ) of 0.95 V, a short-circuit current (J sc ) of 15.60 mA/cm 2 , and a fill factor (FF) of 71.1%, which largely outperforms their binary counterparts. Detailed studies reveal that the ternary solar cells work in a parallel-like device model (ITIC-Th and PC 70 BM form their own independent transport network) when ITIC-Th loading is >30% in the ternary blends. The results indicate that the combination of fullerene derivative and appropriate nonfullerene acceptor in a ternary blend can be a new strategy to fabricate high-performance ternary organic solar cells.

An Alkylated Indacenodithieno[3,2‐b]thiophene‐Based Nonfullerene Acceptor with High Crystallinity Exhibiting Single Junction Solar Cell Efficiencies Greater than 13% with Low Voltage Losses

“…Among the highest performing NFAs, linear rod-like acceptor-donor-acceptor (A-D-A) structures incorporating fused ladder-type aromatics have attracted much interest. Common donor units include 4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene (IDT) [5][6][7][8][9] and 6,12-dihydro-dithienoindeno [10][11][12][13][14][15][16][17][18] In both cases, the fused core facilitates π-electron delocalization and improves the π-π stacking between molecules, hence enhancing the intrinsic charge carrier mobility.In 2015, Zhan and coworkers reported a new NFA, 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11--b′]dithiophene (ITIC) (Scheme 1), which is comprised an electron-donating IDTT-based core flanked by two electron-withdrawing units of 1,1-dicyanomethylene-3-indanone (IC), that exhibited a promising PCE of 6.8% at that time. [10] Since then, many strategies have been applied to modify the structure of ITIC in order to adjust the absorption spectra and energy levels to further improve the PCE, for example, by changing the side chains, [17,18] extending the conjugation length, [19][20][21][22] and substituting the end acceptor groups.…”

“…Among the highest performing NFAs, linear rod-like acceptor-donor-acceptor (A-D-A) structures incorporating fused ladder-type aromatics have attracted much interest. Common donor units include 4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene (IDT) [5][6][7][8][9] and 6,12-dihydro-dithienoindeno [10][11][12][13][14][15][16][17][18] In both cases, the fused core facilitates π-electron delocalization and improves the π-π stacking between molecules, hence enhancing the intrinsic charge carrier mobility.…”

“…[10][11][12][13][14][15][16][17][18] In both cases, the fused core facilitates π-electron delocalization and improves the π-π stacking between molecules, hence enhancing the intrinsic charge carrier mobility.…”

Morphology Control Enables Efficient Ternary Organic Solar Cells

“…[4,5] Consequently, much effort has been devoted to the study of NFA-based ternary OSCs. [46][47][48][49][50][51][52] Ternary organic solar cells are promising alternatives to the binary counterpart due to their potential in achieving high performance. [39][40][41][42][43][44][45] In terms of ternary blend incorporating two NFAs, impressive progresses have been also obtained.…”

“…[21,22] Different ternary blends containing one NFA paired with two donors or one donor/one fullerene derivative exhibited high PCEs over 12%. [46][47][48][49][50][51][52] Ternary organic solar cells are promising alternatives to the binary counterpart due to their potential in achieving high performance. [46][47][48][49][50][51][52] Ternary organic solar cells are promising alternatives to the binary counterpart due to their potential in achieving high performance.…”