A novel wide bandgap conjugated polymer (2.0 eV) based on bithiazole for high efficiency polymer solar cells

Abstract

An efficient wide bandgap conjugated polymer (PTZ6) based on alkoxylphenyl substituted benzodithiophene as donor unit and bithiazole as acceptor unit was developed for polymer solar cells (PSCs). The polymer exhibited a wide bandgap of 2.0 eV with strong absorption in the range of 300-620 nm, and a low-lying highest occupied molecular orbital (HOMO) energy level of-5.36 eV. The PSCs based on PTZ6: PC 71 BM show a PCE of 8.1% with a V oc of 0.96 V, a J sc of 10.9 mA cm-2 and a high FF of 76.7%, which is among the highest values for the fullerene PSCs based on conjugated polymer donors with bandgap near to 2.0 eV. Moreover, for this blend system, the photovoltaic performance of the devices changes little when the active layer thickness increases from 90 nm to 220 nm. More importantly, the non-fullerene PSCs based on PTZ6: ITIC exhibit a PCE of 10.3% with a high V oc of 1.01 V, which should be the best value for the non-fullerene PSCs with the E loss less than 0.6 eV to date. Our results indicate that PTZ6 is a promising wide bandgap polymer donor for the photovoltaic application in PSCs.

Artificial light-harvesting n-type porphyrin for panchromatic organic photovoltaic devices

“…Notably, the V OC value of 0.73 V was remarkably high considering the E g of PDI–P Zn –PDI is only 1.27 eV. The E loss value, defined as E loss = E g – q ⋅ V OC (where q is the elementary charge), 29 , 30 was 0.54 eV, which is much lower than other reported values. 31 …”

Organic Solar Cells Based on High Hole Mobility Conjugated Polymer and Nonfullerene Acceptor with Comparable Bandgaps and Suitable Energy Level Offsets Showing Significant Suppression of Jsc–Voc Trade‐Off

“…Here, we give a summary for single‐junction OSCs with power conversion efficiencies (PCEs) >11% (Figure ). Both binary and ternary blend films for the photoactive layer are included. In Figure , the data are based on over 100 devices, and the points are consecutively numbered, which correspond to their detailed device parameters listed in Table S1, Supporting Information.…”

A1‐A2 Type Wide Bandgap Polymers for High‐Performance Polymer Solar Cells: Energy Loss and Morphology

“…From the initial oxidative wave, the HOMO level of PB24‐3TDC and PB68‐3TDC was estimated to be −5.36 and −5.41 eV, respectively. The HOMO levels of two polymers are lower than those of commonly‐used WBG donors (normally 5.2‐5.3 eV) . This proves that building polymers with dual acceptors is quite effective in lowering the HOMO of the molecule which will facilitate high V oc in devices.…”