Enhanced efficiency of polymer solar cells by adding a high-mobility conjugated polymer

Abstract

The performance of organic solar cells is substantially enhanced by introducing high-mobility conjugate polymers as additives for the first time. The most pronounced effect is observed in one type of device with the average power conversion efficiencies increased from 8.75% to 10.08% after the addition of a high-mobility polymer for only 0.5 weight percent in the active layers, which is mainly attributed to the increased hole mobility and carrier lifetime in the devices. Besides the hole mobility, the energy band structure of the additive is also found to be critical to the enhancement of the device performance. This work demonstrates a novel approach for improving the efficiencies of organic solar cells.

Breaking the 10% Efficiency Barrier in Organic Photovoltaics: Morphology and Device Optimization of Well‐Known PBDTTT Polymers

“…Alternatively, introducing a spectrum-matched donor polymer as the third component in binary PBDTTT polymer:PCBM system can exploit its solar spectrum effectively and a wider range of OPVs have been reported. [96][97][98][99] However, this leads to a much more complicated morphology and charge generation mechanism, and previous efforts have met with only limited success. A famous example was presented by Yu et al, [ 96 ] who reported a ternary blend OPV with a PCE up to 8.3% by combining PTB7 and PID2.…”

“…Recently, the PCE of this type of ternary blend OPV was boosted up to 10.1% by incorporating a high mobility and small band gap DPP polymer, PDVT-10. [ 99 ] To increase the FF of the binary PTB7-Th/PC 71 BM system, Wei's group recently introduced the concept of polymer-small molecule alloys in ternary blend OPVs. In this type of ternary blend OPV, an alloy consisting of a polymer (PTB7-Th) and a small molecule [ p -DTS(FBTTh 2 ) 2 ] acts as the donor material, and PC 71 BM still serves as the acceptor material.…”

Employing inorganic/organic hybrid interface layer to improve electron transfer for inverted polymer solar cells

“…An effective method to reduce exciton recombination and improve injection efficiency is to employ the proper electrodes with matched work functions. Therefore, inorganic buffer layers including TiO x , MoO x , and ZnO between the active layer and cathode have been used to reduce carrier accumulation on the electrode in past few years [15][16][17][18][19][20][21][22]. Ideally, PSCs should have balanced charge transfer and collection to ensure high charge extraction capacity of electrodes, which requires a good interface contact between various layers.…”

Merocyanines for vacuum-deposited small-molecule organic solar cells

“…In order to improve the device performance, various efforts have been made since the past two decades which include (1) synthesizing highly delocalized donor-acceptor (D-A) copolymers or small molecules with various light-harvesting regions as p-type materials (donor) and pristine fullerene or soluble derivatives like PC 61 BM, PC 71 BM, ICBA, as n-type materials (acceptor) [8][9][10]; (2) device engineering for improving exciton diffusion and/or charge transport [11][12][13][14][15][16][17]. The joined efforts have led to outstanding device efficiency and stability.…”