The photoanodes with heterojunction behavior could enable the development of solar energy conversion, but their performance largely suffers from the poor charge separation and transport process through the multiple interfacial energy levels involved. The question is how to efficiently manipulate these energy levels. Taking the n-Si Schottky photoanode as a prototype, the undesired donor-like interfacial defects and its adverse effects on charge transfer in n-Si/ITO photoanode are well recognized and diminished through the treatment on electronic energy level. The obtained n-Si/TiO/ITO Schottky junction exhibits a highly efficient charge transport and a barrier height of 0.95 eV, which is close to the theoretical optimum for n-Si/ITO Schottky contact. Then, the holes extraction can be further facilitated through the variation of surface energy level, with the NiOOH coated ITO layer. This is confirmed by a 115% increase in surface photovoltage of the photoanodes. Eventually, an unprecedentedly low onset potential of 0.9 V (vs RHE) is realized for water oxidation among n-Si photoanodes. For the water oxidation reaction, the n-Si/TiO/ITO/NiOOH photoanode presents a charge separation efficiency up to 100% and an injection efficiency greater than 90% at a wide voltage range. This work identifies the important role of interfacial energetics played in photoelectrochemical conversion.

The high efficiency of planar perovskite solar cells by alternating layer-by-layer vacuum deposition of PbCl2 and CH3NH3I precursor layers is up to 16.03%.

No abstract

Scalable solar hydrogen production by water splitting using particulate photocatalysts is promising for renewable energy utilization. However,p hotocatalytic overall water splitting is challenging owing to slow water oxidation kinetics, severe reverse reaction, and H 2 /O 2 gas separation. Herein, mimicking nature photosynthesis,apractically feasible approach named Hydrogen Farm Project (HFP) is presented, which is composed of solar energy capturing and hydrogen production subsystems integrated by as huttle ion loop,F e 3+ / Fe 2+ .W ell-defined BiVO 4 crystals with precisely tuned {110}/ {010} facets are ideal photocatalysts to realizethe HFP,giving up to 71 %q uantum efficiency for photocatalytic water oxidation and full forward reaction with nearly no reverse reaction. An overall solar-to-chemical efficiency over 1.9 % and as olar-to-hydrogen efficiency exceeding 1.8 %c ould be achieved. Furthermore,ascalable HFP panel for solar energy storage was demonstrated under sunlight outdoors.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Polarization and spin-dependent excited states and charge transport.

Two novel two‐dimensional metal–organic frameworks (2D MOFs), 2D‐M2TCPE (M=Co or Ni, TCPE=1,1,2,2‐tetra(4‐carboxylphenyl)ethylene), which are composed of staggered (4,4)‐grid layers based on paddlewheel‐shaped dimers, serve as heterogeneous photocatalysts for efficient reduction of CO2 to CO. During the visible‐light‐driven catalysis, these structures undergo in situ exfoliation to form nanosheets, which exhibit excellent stability and improved catalytic activity. The exfoliated 2D‐M2TCPE nanosheets display a high CO evolution rate of 4174 μmol g−1 h−1 and high selectivity of 97.3 % for M=Co and Ni, and thus are superior to most reported MOFs. The performance differences and photocatalytic mechanisms have been studied with theoretical calculations and photoelectric experiments. This study provides new insight for the controllable synthesis of effective crystalline photocatalysts based on structural and morphological coregulation.

The solar-to-hydrogen (STH) efficiency of a traditional mono-photoelectrode photoelectrochemical water splitting system has long been limited as large external bias is required. Herein, overall water splitting with STH efficiency exceeding 2.5% was achieved using a self-biased photoelectrochemical-photovoltaic coupled system consisting of an all earth-abundant photoanode and a Si-solar-cell-based photocathode connected in series under parallel illumination. We found that parallel irradiation mode shows higher efficiency than tandem illumination especially for photoanodes with a wide light absorption range, probably as the driving force for water splitting reaction is larger and the photovoltage loss is smaller in the former. This work essentially takes advantage of a tandem solar cell which can enhance the solar-to-electricity efficiency from another point of view.

to the electronic and morphological parameters in the active perovskite layer, the electron transport layer (ETL) and hole transport layer (HTL) are significantly important in determining the photovoltaic performance in perovskite solar cells. [3][4][5][6] Specifically, the role of a transport layer in solar cells is to facilitate charge transport and assist charge collection toward the respective electrodes as well as inhibiting from recombination of charge carriers on the path to the electrodes. [3] Meanwhile, the open circuit voltage (V oc ) is normally determined by the energy differences between the Fermi levels of the ETL and the HTL. There are certain prerequisites for a hole transport material in order to perform more efficiently in perovskite solar cells, such as energy band alignment, suitable hole mobility, chemical compatibility with the perovskite layer as well as good thermal and photochemical stability. [5,6] In addition, morphology and crystallinity of this layer plays an important role. The importance and influence of these parameters in the transport layer on perovskite solar cells performance have been extensively investigated. [3,[5][6][7][8][9][10] In this article, we demonstrate the importance of photogenerated dipoles in the HTL as a new strategy to improve the photovoltaic performance of planar perovskite solar cells. In order to explore this effect, we select two HTLs with similar conjugated thiophene backbones, namely PTB7 and P3HT with significant and negligible optically generated dipoles. Moreover, our measurements based on space charge limited current model indicate that PTB7 and P3HT have hole mobilities in the same order in agreement with previous publications (Figure S1, Supporting Information). [11][12][13][14] It has been shown that PTB7 has a relatively large internal dipoles through intrachain charge transfer from benzodithiophene to thienothiophene moieties under photoexcitation. [15] The dipole moments (D) in ground and excite states have been measured to be 3.76 and 7.13 for PTB7 and 0.19 and 0.43 for P3HT, respectively. [15] In general, perovskites have the advantage of both bulk polarization and semiconducting properties. [16][17][18][19][20] It was shown that the presence of a polar molecule, methylammonium at the center of perovskite introduces the possibility of orientational P3HT-poly(3-hexylthiophene) are separately used as the HTL with significant and negligible photoinduced dipoles, respectively. Electric field-induced photoluminescence quenching provides the first-hand evidence to indicate that the photoinduced dipoles are partially aligned in the amorphous PTB7 layer under the influence of device built-in field. By monitoring the recombination process through magneto-photocurrent measurements under device operation condition, it is shown that the photoinduced dipoles in PTB7 layer can decrease the recombination of photogenerated carriers in the active layer in perovskite solar cells. Furthermore, the capacitance measurements suggest that the photoinduced dipoles ...