8.0% Efficient All‐Polymer Solar Cells with High Photovoltage of 1.1 V and Internal Quantum Efficiency near Unity

Abstract

In very recent years, growing efforts have been devoted to the development of all‐polymer solar cells (all‐PSCs). One of the advantages of all‐PSCs over the fullerene‐based PSCs is the versatile design of both donor and acceptor polymers which allows the optimization of energy levels to maximize the open‐circuit voltage (Voc). However, there is no successful example of all‐PSCs with both high Voc over 1 V and high power conversion efficiency (PCE) up to 8% reported so far. In this work, a combination of a donor polymer poly[4,8‐bis(5‐(2‐octylthio)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl‐alt‐(5‐(2‐ethylhexyl)‐4H‐thieno[3,4‐c]pyrrole‐4,6(5H)‐dione)‐1,3‐diyl] (PBDTS‐TPD) with a low‐lying highest occupied molecular orbital level and an acceptor polymer poly[[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐thiophene‐2,5‐diyl] (PNDI‐T) with a high‐lying lowest unoccupied molecular orbital level is used, realizing high‐performance all‐PSCs with simultaneously high Voc of 1.1 V and high PCE of 8.0%, and surpassing the performance of the corresponding PC71BM‐based PSCs. The PBDTS‐TPD:PNDI‐T all‐PSCs achieve a maximum internal quantum efficiency of 95% at 450 nm, which reveals that almost all the absorbed photons can be converted into free charges and collected by electrodes. This work demonstrates the advantages of all‐PSCs by incorporating proper donor and acceptor polymers to boost both Voc and PCEs.

Side‐Chain Impact on Molecular Orientation of Organic Semiconductor Acceptors: High Performance Nonfullerene Polymer Solar Cells with Thick Active Layer over 400 nm

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In recent years, n-type organic semiconductor (n-OS) (or called as nonfullerene) acceptors have been gaining their popularity in low production cost, light weight, flexible and large-area applications in polymer solar cells (PSCs) due to their excellent optical absorption, tunable energy levels, facile synthesis, and good solution-processability. [14,[17][18][19][20][21][22][23][24][25][26][27][28][29] And the n-OS acceptors-based devices have achieved power conversion efficiency (PCE) as high as over 12%. [14,[17][18][19][20][21][22][23][24][25][26][27][28][29] And the n-OS acceptors-based devices have achieved power conversion efficiency (PCE) as high as over 12%.

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High‐Efficiency Polymer Solar Cells Over 13.9% With a High VOC Beyond 1.0 V by Synergistic Effect of Fluorine and Sulfur

“…It exhibits a defined absorption profile with two strong peaks at about 537 and 577 nm in solution, which belong to charge transfer transition and inter‐chain aggregation absorption, respectively. It is inferred that there should be strong intermolecular aggregation in solution . And the film state absorption spectrum of PBTA‐PSF was red‐shifted compared to that of the solution.…”

Imide‐Functionalized Polymer Semiconductors

“…reported high‐performance all‐PSCs utilizing 21 as the acceptor polymer and D9 (Figure ) as the donor polymer. Owing to the broad absorption, and the downshifted HOMO level enabled by alkylthio‐substitution, a PCE of 8.0 % was attained with an ultra‐high V oc of 1.10 V and a large FF of 63 % . Ma and co‐workers synthesized NDI–selenophene based copolymers 20 and 24 to investigate the structure–property–performance correlations.…”