The balance property in neural network modelling

In estimation and prediction theory,considerable attention is paid to the question of hav-ing unbiased estimators on a global population level.Recent developments in neural network modelling have mainly focused on accuracy on a granular sample level,and the question of unbi-asedness on the population level has almost completely been neglected by that community.We discuss this question within neural network regression models,and we provide methods of receiving unbiased estimators for these models on the global population level.

Understanding the role of interconnecting layer on determining monolithic perovskite/organic tandem device carrier recombination properties

As one of the core parts of two-terminal(2 T) monolithic tandem photovoltaics, the interconnecting layers(ICLs) play a critical role in modulating the carrier transport and recombination between the sub-cells,and thus influencing the tandem device performance. Here, for the first time, the relationship between ICLs architecture and 2 T monolithic perovskite/organic tandem device performance has been studied by investigating the change of ICLs composition layer thickness on the ICLs optical and electrical properties, sub-cells EQE properties, and tandem device J-V properties. It is revealed that the ability of ICLs on modulating the sub-cells carrier balance properties is strongly associated with its composited layers thickness, and the tandem device carrier balance properties can be reflected by the relative EQE intensity between the sub-cells. Finally, with a deep understanding of the mechanisms, rational design of ICLs can be made to benefit the tandem device development. Based on the optimized ICL a high PCE of 20.03% is achieved.

Well-balanced ambipolar diketopyrrolopyrrole-based copolymers for OFETs,inverters and frequency doublers

Conjugated polymers with well-balanced ambipolar charge transport is essential for organic circuits at low cost and large area with simplified fabrication techniques.Aiming at this point,herein,a novel asymmetric thiophene/pyridine-flanked diketopyrrolopyrrole-based copolymer(PPyTDPP-2FBT)is designed and synthesized.Due to the effect of incorporating F atoms on molecular energy alignment and conjugation conformation,the PPyTDPP-2FBT copolymer exhibits typical V-shaped ambipolar field-effect transfer characteristics with well-balanced hole and electron mobilities of 0.64 and 0.46 cm^(2)V^(−1)s^(−1),respectively.Furthermore,organic digital and analog circuits such as inverters and frequency doublers are successfully constructed based on solution-processed films of the PPyTDPP-2FBT copolymers which show a typical circuit operating mode with a high gain of 133 due to the well-balanced electrical properties.In addition,PPyTDPP-2FBT-based devices also demonstrate good stability and batch repeatability,suggesting their great potential applications in organic integrated electronic circuits.