Dion-Jacobson (DJ) phase 2D layered perovskites are developed by removing the van der Waals gap between organic layers and inorganic slabs in Ruddlesden-Popper (RP) phase counterparts. The hydrogen bonding formed at both sides of diammonium cations with perovskite layers in the DJ phase 2D perovskite endows it with extremely high structural stability, compared with that at only one side in the RP phase one. The devices exhibit a PCE of 13.3% with unprecedented stability, even when subjected to very harsh testing conditions.

The integrated architecture enables the Ta3N5photoanode to approach the theoretical photocurrent limit for solar water splitting.

It has been anticipated that learning from nature photosynthesis is a rational and effective way to develop artificial photosynthesis system, but it is still a great challenge. Here, we assembled a photoelectrocatalytic system by mimicking the functions of photosystem II (PSII) with BiVO semiconductor as a light harvester protected by a layered double hydroxide (NiFeLDH) as a hole storage layer, a partially oxidized graphene (pGO) as biomimetic tyrosine for charge transfer, and molecular Co cubane as oxygen evolution complex. The integrated system exhibited an unprecedentedly low onset potential (0.17 V) and a high photocurrent (4.45 mA cm), with a 2.0% solar to hydrogen efficiency. Spectroscopic studies revealed that this photoelectrocatalytic system exhibited superiority in charge separation and transfer by benefiting from mimicking the key functions of PSII. The success of the biomimetic strategy opened up new ways for the rational design and assembly of artificial photosynthesis systems for efficient solar-to-fuel conversion.

With the ZnO/IL interfacial layer, PTB7-Th : PC71BM i-PSCs can exhibit a champion PCE of 10.15%.

Developing superior deep-ultraviolet (deep-UV) nonlinear optical (NLO) materials is a great challenge because of the contradiction between deep-UV transparency and enhanced second harmonic generation (SHG), especially for deep-UV NLO phosphates in which the constituent P−O groups have relatively small microscopic SHG coefficients. Here we report a new noncentrosymmetric phosphate Cs 2 LiPO 4 (I), whose crystal structure consists of [LiPO 4 ] ∞ layered structural units with a novel honeycomb-like topology. As compared with the benchmark deep-UV NLO material KBe 2 BO 3 F 2 , I is beryllium-free, and it is relatively easy to grow its large single crystals because of its congruent melting. Furthermore, it not only is deep-UV transparent but also exhibits an unexpectedly enhanced SHG response of 1.8 × KH 2 PO 4 that hits a new high in deep-UV NLO phosphates. These results demonstrate that I satisfies the key requirements of being a promising deep-UV NLO candidate. Theory calculations and structural analysis reveal that the enhanced SHG response can be attributed to the honeycomb-like topological structure, which endows the constituent [PO 4 ] 3− monomers of I with an aligned arrangement and as a result a favorable superposition of their microscopic SHG coefficients. These findings may provide useful insights into the development of both deep-UV NLO materials and honeycomb-like topological structures.

Inspired by the structural feature of the classical hole-transport material (HTM), Spiro-OMeTAD, many analogues based on a highly symmetrical spiro-core were reported for perovskite solar cells (PSCs). However, these HTMs were prone to crystallize because of the high molecular symmetry, forming non-uniform films, unfavorable for the device stability and large-area processing. By lowering the symmetry of spiro-core, we report herein a novel spirobisindane-based HTM, Spiro-I, which could form amorphous films with high uniformity and morphological stability. Compared to the Spiro-OMeTAD-based PSCs, those containing Spiro-I exhibit similar efficiencies for small area but higher ones for large area (1 cm ), and especially much higher air stability (retaining 80 % of initial PCE after 2400 h storage without encapsulation). Moreover, the Spiro-I can be synthesized from a cheap starting material bisphenol A and used with a small amount for the device fabrication.

One of the major hurdles that impedes the practical application of photoelectrochemical (PEC) water splitting is the lack of stable photoanodes with low onset potentials. Here, we report that the Ni(OH)x/MoO3 bilayer, acting as a hole-storage layer (HSL), efficiently harvests and stores holes from Ta3N5, resulting in at least 24 h of sustained water oxidation at the otherwise unstable Ta3N5 electrode and inducing a large cathodic shift of ≈600 mV in the onset potential of the Ta3N5 electrode.

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