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Non-fullerene acceptor (NFA)-based organic solar cells have made tremendous progress in recent years. For the neat NFA system PBDB-T:ITIC, the film morphology and crystallinity are tailored by the choice of the solvent used for spin coating the active layers. Three different chlorinated solvents, chlorobenzene (CB), chloroform, and dichlorobenzene, are compared and the obtained active layer morphology is correlated with the optoelectronic properties and the device performance. The small domain sizes in the case of CB are most beneficial for the device performance, whereas the largest number or size of face-on PBDB-T crystallites is not causing the highest power conversion efficiencies (PCEs). In addition, when using CB, the number of edge-on crystallites is highest and the distances between neighboring domains are small. The smoothest blend films are realized with CB, which exhibit correlated roughness with their substrates and no large aggregates have formed in these blend films. Thus, CB offers the best way to balance the aggregation and crystallization kinetics in the active layer and enables the highest PCE values., QC 20221109

While tremendous progress has recently been made in perovskite light-emitting diodes (PeLEDs), large-area blue devices feature inferior performance due to uneven morphologies and vast defects in the solution-processed perovskite films. To alleviate these issues, a facile and reliable interface engineering scheme is reported for manipulating the crystallization of perovskite films enabled by a multifunctional molecule 2-amino-1,3-propanediol (APDO)-triggered “anchoring effect” at the grain-growth interface. Sky-blue perovskite films with large-area uniformity and low trap states are obtained, showing the distinctly improved radiative recombination and hole-transport capability. Based on the APDO-induced interface engineering, synergistical boost in device performance is achieved for large-area sky-blue PeLED (measuring at 100 mm2) with a peak external quantum efficiency (EQE) of 9.2% and a highly prolonged operational lifetime. A decent EQE up to 6.1% is demonstrated for the largest sky-blue device emitting at 400 mm2. © 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.

In recent years, copper redox mediators have attracted growing interest in dye-sensitized solar cells (DSCs). However, experiments revealed that ubiquitously used Lewis-base additives in the electrolytes coordinate to the CuII species, which restricts further enhancement of device performance and stability. We report the application of copper complexes endowed with diamine-tripyridine pentadentate ligands, [Cu(tpe)]2+/+ (tpe=N-benzyl-N,N′,N′-tris(pyridin-2-ylmethyl)ethylenediamine) and [Cu(tme)]2+/+ (tme=N-benzyl-N,N′,N′-tris(6-methylpyridin-2-ylmethyl)ethylenediamine), as redox mediators in DSCs. Experimental measurements demonstrate that the coordination environment of Cu(II) complexes with pentadentate ligands remains unchanged in the presence of TBP, which is in stark contrast to the state-of-the-art bipyridyl counterpart. DSCs based on [Cu(tme)]2+/+ complexes exhibit an excellent long-term stability and maintain more than 90 % of the initial efficiency after 400 h under continuous illumination, which outperform the reference devices incorporating the bipyridyl counterpart (less than 80 %) under identical conditions., QC 20220318

In times where research focuses on the use of organic polymers as a base for complex organic electronic applications and improving device efficiencies, degradation is still less intensively addressed in fundamental studies. Hence, advanced neutron scattering methods are applied to investigate a model system for organic electronics composed of the widely used conductive polymer blend poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) together with nanocellulose as flexible reinforcing template material. In particular, the impact of relative humidity (RH) on the nanostructure evolution is studied in detail. The implications are discussed from a device performance point of view and the changing nanostructure is correlated with macroscale physical properties such as conductivity. The first humidification (95% RH) leads to an irreversible decrease of conductivity. After the first humidification cycle, however, the conductivity can be reversibly regained when returning to low humidity values (5% RH), which is important for device manufacturing. This finding can directly contribute to an improved usability of emerging organic electronics in daily live., QC 20220228

Additives treatment is as a very effective strategy to optimize bulk heterojunction (BHJ) morphology. However, the inherent working mechanism of this strategy still lacks systematical investigations in non-fullerene-acceptors-based organic solar cells (OSCs). Herein, a series of BHJ and pseudo-planar heterojunction (PPHJ) OSCs using PM6 and IT-4F as the electron donor/acceptor pair, are developed to unveil the promoting effect of solvent additive 1, 8-diiodooctane (DIO) on active layer morphologies and device performance. The study clearly demonstrates that DIO can increase the crystallinity of IT-4F significantly, while it has less impact on PM6. It is notable that a new efficiency-determining crystalline balanced factor (CCLpolymer/CCLacceptor) is put forward, indicating that the more balanced CCLpolymer/CCLacceptor results in more balanced charge mobility and much better short-circuit current densities (Jsc) and fill factors (FF) of OSCs. The PPHJ blend film of PM6/IT-4F(DIO) exhibits enhanced crystallinity with more balanced CCL and favorable hierarchical distribution morphology, contributing to a champion efficiency of 13.70% with a record Jsc of 20.98 mA cm−2 and a remarkable FF of 75.9%. This work not only reveals the underlying mechanism of DIO caused morphology evolution, but also achieves highly efficient PPHJ OSCs with superior thermal stability by elaborately controlling the morphology of PPHJ film., QC 20211108