16.52% Efficiency All‐Polymer Solar Cells with High Tolerance of the Photoactive Layer Thickness

Abstract

All‐polymer solar cells (all‐PSCs) have drawn growing attention and achieved tremendous progress recently, but their power conversion efficiency (PCE) still lags behind small‐molecule‐acceptor (SMA)‐based PSCs due to the relative difficulty on morphology control of polymer photoactive blends. Here, low‐cost PTQ10 is introduced as a second polymer donor (a third component) into the PM6:PY‐IT blend to finely tune the energy‐level matching and microscopic morphology of the polymer blend photoactive layer. The addition of PTQ10 decreases the π–π stacking distance, and increases the π–π stacking coherence length and the ordered face‐on molecular packing orientation, which improves the charge separation and transport in the photoactive layer. Moreover, the deeper highest occupied molecular orbital energy level of the PTQ10 polymer donor than PM6 leads to higher open‐circuit voltage of the ternary all‐PSCs. As a result, a PCE of 16.52% is achieved for ternary all‐PSCs, which is one of the highest PCEs for all‐PSCs. In addition, the ternary devices exhibit a high tolerance of the photoactive layer thickness with high PCEs of 15.27% and 13.91% at photoactive layer thickness of ≈205 and ≈306 nm, respectively, which are the highest PCEs so far for all‐PSCs with a thick photoactive layer.

A New Polymer Donor Enables Binary All‐Polymer Organic Photovoltaic Cells with 18% Efficiency and Excellent Mechanical Robustness

“…[38,39] Generally, the morphology of blend films plays a vital role in charge separation and transport. [40] Atomic force microscopy (AFM) and grazing-incidence wide-angle X-ray scattering (GIWAXS) were conducted to investigate the morphology of films. The results of AFM are shown in Figure 4 and Figure S11 in the Supporting Information.…”

Efficient All-Polymer Solar Cells with Sequentially Processed Active Layers

“…As shown in the upper part of Figure 1 c, it was obtained by one-step blend-casting (BC) from the donor PM6 and acceptor PY-IT mixed solution. The sequential processing (SqP) with the underlayer donor PM6 and the upper acceptor PY-IT, being sequentially spin-casted, is presented in the lower part of Figure 1 c. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the active-layer materials ( Figure 1 d) were taken from the literature [ 33 , 34 ].…”

Realizing the efficiency-stability balance for all-polymer photovoltaic blends

“…[31][32][33] In recent years, the new types of polymerized small molecular acceptors endow the polymer-polymer device with a rapid increase in PCE. [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] However, this type of all-polymer blend exhibits a poorer stability due to the low molecular weight. Accordingly, material designs based on current, mature, efficient all-polymer systems aiming to promote the stability of the morphology should be a meaningful strategy.…”