Polymer Acceptor Based on Double B←N Bridged Bipyridine (BNBP) Unit for High‐Efficiency All‐Polymer Solar Cells

Abstract

A novel polymer acceptor based on the double B←N bridged bipyridine building block is reported. All-polymer solar cells based on the new polymer acceptor show a power conversion efficiency of as high as 6.26% at a photon energy loss of only 0.51 eV.

Thieno[3,4‐c]Pyrrole‐4,6‐Dione‐Based Polymer Acceptors for High Open‐Circuit Voltage All‐Polymer Solar Cells

“…6%. [30] Several other acceptor motifs are being examined, such as diketopyrrolopyrrole, [31] benzothiadiazole, [32][33] isoindigo, [34] and various nitrile(CN)-derived motifs; [1,35] with reported PCEs in range of 1-4%. However, to date, polymer acceptor developments remain synthetically challenging, and the manifold of electron-deficient motifs and polymer acceptor candidates that can rival fullerenes for efficient BHJ solar cells with polymer donors remains modest.…”

“…However, to date, polymer acceptor developments remain synthetically challenging, and the manifold of electron-deficient motifs and polymer acceptor candidates that can rival fullerenes for efficient BHJ solar cells with polymer donors remains modest. [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] Further examinations of the "all-polymer" BHJ concept require that the class of polymer acceptors that can potentially outperform fullerenes be widened and, at this stage, forging a better understanding of the design parameters that directly impact polymer acceptor performance in BHJ solar cells is a key step towards high-performing material systems and BHJ devices.…”

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

“…As clarified in recent reports, reduced E loss is beneficial for improving V oc of the PSCs. [30,34,[49][50][51] Considering both the energy level alignment and the photon energy losses, the up-lying LUMO level of PNDI-T and the lower E loss can explain the higher V oc in the two all-PSCs.…”

“…The high-performance all-PSCs with PCEs over 7% only afford moderate V oc around 0.8 V, [18,22,24,26,28] whereas a few all-PSCs can emerge high V oc around 1.0 V, but the PCEs never surpass 7%. [20,[29][30][31][32] In contrast, a PC 71 BM-based PSC with a high V oc close to 1 V and a high PCE of 8.9% has been realized. [33] A nonfullerene PSC based on a polymer/small molecule blend also attained a high V oc of 1.12 V with a high PCE approaching 10%.…”

Enhanced power conversion efficiency in iridium complex-based terpolymers for polymer solar cells

“…3,[10][11][12][13] (ii) To overcome the shortcomings of fullerenes, such as weak absorption in the solar spectrum range, limited structural and energy level variability as well as device instability of the most widely used fullerene acceptors, the exploration of high performance new non-fullerene electron acceptors which comprise electron-deficient building blocks with low-lying HOMO and lowest unoccupied molecular orbital energy levels, strong absorption and high electron mobilities finds increasing attention in the field of OSCs. [14][15][16][17][18][19] (iii) The involvement of suitable anode or cathode interface materials to reduce the interfacial energy barriers and facilitate an efficient hole or electron extraction from the active layer have also been demonstrated as effective approaches to enhance the PCE. 20,21 From the device engineering side, (iv) the introduction of ternary structures in the active layer with two-donors/one-acceptor or two-acceptors/one-donor to enhance the absorption and increase the short-circuit current (J sc ), 8,[22][23][24][25][26] (v) the use of tandem structures including two or more subcells connected in series with complementary absorption bands to reduce the thermalization losses and increase the open-circuit voltages (V oc ) [27][28][29] and (vi) the optimization of the film morphology of the active layer adopting solvent vapor annealing, thermal annealing, mixed solvent and/or solvent additives have also been proved to be successful methods to achieve high performance OSCs.…”