Temperature-modulated space-charge-limited-current spectroscopy (TMSCLC) is applied to quantitatively evaluate the density of trap states in the band-gap with high energy resolution of semiconducting hybrid lead halide perovskite single crystals. Interestingly multicomponent deep trap states were observed in the pure perovskite crystals, which assumingly caused by the formation of nanodomains due to the presence of the mobile species in the perovskites.

Versatile approaches to nanoparticle synthesis offer unprecedented opportunities for the development of optoelectronics, photonics, as well as bio sciences. With the current advancement of hybrid organic-inorganic metal halide perovskites, the next step is to expand their field of applications via utilization of functional and modifiable ligand chemistry. Here, we present a ligand assisted reprecipitation approach for highly luminescent perovskite nanoparticle synthesis using for the first time L-lysine and L-arginine for surface passivation. These nanoparticles exhibit emission within a narrow bandwidth of the visible spectrum and photoluminescence quantum yield close to 100%. Additionally, preferential ligand orientation is achieved via amino acids α-amino group blocking which results in blueshifted emission as well as smaller and more uniform particle size. These experimental results demonstrate the effectiveness of naturally occurring proteinogenic amino acids as surface ligands and offer possibilities for versatile modification of perovskite nanoparticle properties via well-studied amino acid chemistry.

The origin of a negative capacitance observed in perovskite solar cells at intermediate and low frequencies remains unclear. Low trap density macroscopic single crystal MAPbBr3 perovskites, prepared by means of an inverse temperature crystallization technique, with symmetric Au contacts is used to avoid the influence of defects and provide the information ongoing staunchly in the perovskite material. It is shown that the inductive behavior is dominant in the frequency range where capacitance possesses negative values. Accordingly, a model for the calculation of inductive elements and the description of their origin is presented. It is shown that, at high bias, there are two bias‐dependent inductive elements, which corresponds to two different components of vacancy‐assisted ionic diffusion in perovskite crystals, originating from Br– and MA+ ions.

A series of copolymers containing a glycolated 1,4‐dithienyl‐2,3,5,6‐tetrafluorophenylene unit copolymerized with thiophene, bithiophene, thienothiophene and 1,2,4,5‐tetrafluorobenzene comonomer units were designed and synthesised by direct heteroarylation polymerisation. The optical, electrochemical, electrochromic and solid‐state structural properties of the copolymers were investigated. The copolymers exhibit stable redox properties in organic solvents and promising redox properties in thin film configuration with an aqueous electrolyte. Finally, the potential of the copolymers as active materials in organic electrochemical transistors (OECTs) was assessed, and promising performance was shown as an accumulation‐mode OECT material with a peak transconductance of 0.17 mS and a good on/off ratio of 105 for the thiophene copolymer.

The singlet fission (SF) process discovered in bis(thienyl) diketopyrrolopyrroles (TDPPs) can boost their potential for photovoltaics (PV). The crystal structures of TDPP analogs carrying n-hexyl, n-butyl, or 2-(adamant-1-yl)ethyl substituents are similar, but contain increasingly slipped stacked neighbor molecules. The observed SF rate constants, k SF , (7 � 4), (9 � 3) and (5.6 � 1.9) ns À 1 for thin films of the three compounds, respectively, are roughly equal, but the triplet quantum yields vary strongly: (120 � 40), (160 � 40) and (70 � 16), respectively. The recent molecular pair model reproduces the near equality of all three k SF at the crystal geometries and identifies all possible pair arrangements in which SF is predicted to be faster, by up to two orders of magnitude. However, it is also clear that the presently non-existent ability to predict the rates of processes competing with SF is pivotal for providing a guide for efforts to optimize the materials for PV.