Polymer Acceptors with Flexible Spacers Afford Efficient and Mechanically Robust All‐Polymer Solar Cells

Abstract

High efficiency and mechanical robustness are both crucial for the practical applications of all‐polymer solar cells (all‐PSCs) in stretchable and wearable electronics. In this regard, a series of new polymer acceptors (PAs) is reported by incorporating a flexible conjugation‐break spacer (FCBS) to achieve highly efficient and mechanically robust all‐PSCs. Incorporation of FCBS affords the effective modulation of the crystallinity and pre‐aggregation of the PAs, and achieves the optimal blend morphology with polymer donor (PD), increasing both the photovoltaic and mechanical properties of all‐PSCs. In particular, an all‐PSC based on PYTS‐0.3 PA incorporated with 30% FCBS and PBDB‐T PD demonstrates a high power conversion efficiency (PCE) of 14.68% and excellent mechanical stretchability with a crack onset strain (COS) of 21.64% and toughness of 3.86 MJ m‐3, which is significantly superior to those of devices with the PA without the FCBS (PYTS‐0.0, PCE = 13.01%, and toughness = 2.70 MJ m‐3). To date, this COS is the highest value reported for PSCs with PCEs of over 8% without any insulating additives. These results reveal that the introduction of FCBS into the conjugated backbone is a highly feasible strategy to simultaneously improve the PCE and stretchability of PSCs.

Intrinsically Stretchable Organic Solar Cells with Simultaneously Improved Mechanical Robustness and Morphological Stability Enabled by a Universal Crosslinking Strategy

“…[ 25,26 ] Furthermore, Wang and co‐workers synthesized the novel polymer acceptors with flexible spacers to increase the PCE and stretchability of OSCs. [ 27 ]…”

“…[25,26] Furthermore, Wang and co-workers synthesized the novel polymer acceptors with flexible spacers to increase the PCE and stretchability of OSCs. [27] The long-term operation stability of OSCs is another major concern for practical applications. [28][29][30] The degradation pathways of OSCs may originate from the instability of materials or the active layer film morphology change under humidity, oxygen, thermal, and light exposure.…”

Sequentially Fluorinated Polythiophene Donors for High‐Performance Organic Solar Cells with 16.4% Efficiency

“…As a result, the PT-4F blend exhibited a more balanced mobility ratio (µ e /µ h ) of 1.1, preventing the accumulation of space charge and enabling higher J sc and FF values, while the PT-2F blend had a less balanced µ e /µ h of 3.8. [24] Charge recombination behavior was evaluated by tracking the changes of V oc and J sc depending on incident light intensity (P light ). [25] The J sc and P values follow the power-law relationship of J sc ∝ P light α , where α approaches unity as bimolecular recombination is suppressed.…”

Thermomechanical Behavior of Poly(3-hexylthiophene) Thin Films on the Water Surface

“…For quantitative analysis, we estimated the coherence length ( L c ) values of the (200) peaks in the OOP direction based on the Scherrer equation ( Figure S8 ). 65 , 66 The L c of P3HT films preheated on PSS/glass increased with higher T pre , suggesting that the crystalline domain sizes of P3HT became larger and that the polymer chains were arranged into more-ordered fashion at higher temperatures. For instance, the as-cast P3HT film exhibited L c = 9.5 nm, and it increased to 10.1 nm at T pre = 50 °C, and to 11.1 nm at T pre = 150 °C.…”