Non-fullerene acceptor organic photovoltaics with intrinsic operational lifetimes over 30 years

Abstract

Organic photovoltaic cells (OPVs) have the potential of becoming a productive renewable energy technology if the requirements of low cost, high efficiency and prolonged lifetime are simultaneously fulfilled. So far, the remaining unfulfilled promise of this technology is its inadequate operational lifetime. Here, we demonstrate that the instability of NFA solar cells arises primarily from chemical changes at organic/inorganic interfaces bounding the bulk heterojunction active region. Encapsulated devices stabilized by additional protective buffer layers as well as the integration of a simple solution processed ultraviolet filtering layer, maintain 94% of their initial efficiency under simulated, 1 sun intensity, AM1.5 G irradiation for 1900 hours at 55 °C. Accelerated aging is also induced by exposure of light illumination intensities up to 27 suns, and operation temperatures as high as 65 °C. An extrapolated intrinsic lifetime of > 5.6 × 104 h is obtained, which is equivalent to 30 years outdoor exposure.

Simultaneously Achieving Highly Efficient and Stable Polymer:Non‐Fullerene Solar Cells Enabled By Molecular Structure Optimization and Surface Passivation

“…[ 24 ] By comparing the stability difference of the IT‐4F cells with different ZnO interlayer, we recently proved that photon generated hydroxyl radicals on the ZnO surface is the chemical reactive species that causes the breaking of the C═C bonds. [ 25 ] With the better understanding on the detailed degradation mechanism of the NFA cells, methods to improve device stability, including blending with fullerene molecules, [ 26 ] surface treatment with Lewis acids, [ 27 ] a thin PEI layer, [ 28 ] or a self‐assembled monolayer [ 29 ] were reported, supporting the proposed degradation mechanism. Despite these excellent research works in improving the stability of the cells, these cells showed lower initial efficiencies less than the optimized cell performance, and most of the cells showed a PCE lower than 15%.…”

On the interface reactions and stability of nonfullerene organic solar cells

“…Recently, Forrest et al 94 tested several modification/buffer materials for enhancing device reliability ( Fig. 22a ).…”

Donor–Acceptor Copolymers with Rationally Regulated Side Chain Orientation for Polymer Solar Cells Processed by Non-Halogenated Solvent

“…Polymer solar cells (PSCs) have attracted extensive research attention and achieved rapid development in recent years due to their advantages of light weight, flexibility and feasibility of roll-to-roll process. [1][2][3][4][5][6] Active layer materials with bulk heterojunction (BHJ) structure formed by mechanical blending are important components of PSCs, which are usually composed of p-type polymer electron donors and ntype small molecule or polymer electron acceptors. [7][8][9] In the past few years, the power conversion efficiency (PCE) of PSCs has been boosted from 10 % to over 18 % because of the rapid development of various non-fullerene small molecular acceptors (NFSMAs) and polymer donors.…”