Highly Efficient and Stable FAPbI_(3) Perovskite Solar Cells and Modules Based on Exposure of the(011)Facet

Perovskite crystal facets greatly impact the performance and stability of their corresponding photovoltaic devices.Compared to the(001)facet,the(011)facet yields better photoelectric properties,including higher conductivity and enhanced charge carrier mobility.Thus,achieving(011)facet-exposed films is a promising way to improve device performance.However,the growth of(011)facets is energetically unfavorable in FAPbI_(3) perovskites due to the influence of methylammonium chloride additive.Here,1-butyl-4-methylpyridinium chloride([4MBP]Cl)was used to expose(011)facets.The[4MBP]^(+)cation selectively decreases the surface energy of the(011)facet enabling the growth of the(011)plane.The[4MBP]^(+)cation causes the perovskite nuclei to rotate by 45°such that(011)crystal facets stack along the out-of-plane direction.The(011)facet has excellent charge transport properties and can achieve better-matched energy level alignment.In addition,[4MBP]Cl increases the activation energy barrier for ion migration,suppressing decomposition of the perovskite.As a result,a small-size device(0.06 cm2)and a module(29.0 cm2)based on exposure of the(011)facet achieved power conversion efficiencies of 25.24%and 21.12%,respectively.

Novel photoelectric material of perovskite-like(CH_(3))_(3)SPbI_(3) nanorod arrays with high stability

Organometallic halide perovskite materials make great achievements in optoelectronic fields,especially in solar cells,in which the organic cations contain amine components.However,the amine with NàH bonds is easily hydrolyzed with moisture in the air,weakening the perovskite materials stability.It is desirable to develop other non-amine stable perovskite materials.In this work,sulfur-based perovskite-like(CH_(3))_(3)SPbI_(3) nanorod arrays were fabricated by a solution-processed method,which can be indexed hexagonal crystal structure in the space group P63 mc.The binding force is exceptionally strong between the non-amine(CH_(3))_(3) S+and[PbI_(6)]_(4)-octahedral,leading to high stability of(CH_(3))_(3)SPbI_(3).The(CH_(3))_(3)SPbI_(3) nanorod arrays can keep the morphology and crystal structure in an ambient atmosphere over 60 days.In addition,the(CH_(3))_(3)SPbI_(3) nanorod arrays can offer direct charge transfer channels,which show excellent optoelectronic properties.The(CH_(3))_(3)SPbI_(3) nanorod arrays-based solar cells with VOx hole transfer layers achieved a power conversion efficiency of 2.07%with negligible hysteresis.And the(CH_(3))_(3)SPbI_(3) nanorod arrays were also effectively applied in photodetectors with interdigitated gold electrodes.This work demonstrates that sulfur-based perovskite-like(CH_(3))_(3)SPbI_(3) is a novel promising stable compound with great potential for practical optoelectronic applications.

Methodical review of the literature referred to the dye-sensitized solar cells: Bibliometrics analysis and road mapping

This study presents a systematic review of the literature pertaining to dye-sensitized solar cells(DSSCs), in order to anticipate the direction and speed of change in technology trend. To study the general progression in DSSC research, we have assessed the evolution in annual DSSCs publications and their citations. Further, in order to identify the intellectual bases, we have also classified the journals, authors, institutes, and countries according to their scientific productivity in the field of DSSCs research during the period of 2007–2017.

A Triethyleneglycol C60 Mono-adduct Derivative for Efficient Electron Transport in Inverted Perovskite Solar Cells

Inverted perovskite solar cells(PSCs)have attracted increasing attention in recent years owing to their low-temperature fabrication proces s.However,they suffer from a limited number of electron transport materials available with[6,6]-phenyl C61 butyric acid methyl ester(PCBM)to be the most widely studied based on its appropriate energy levels and high electron mobility.The low relative permittivity and aggregation tendency upon illumination of PCBM,however,compromises the solar cell efficiency whereas its modest hydrophobicity negatively impacts on the device stability.Alternative electron transport materials with desired properties and appropriate degree of hydrophobicity are thus desirable for further developments in inverted PSCs.Herein,we synthesize a triethyleneglycol C60 mono-adduct derivative(termed as EPF03)and test it as a novel electron transport material to replace PCBM in inverted PSCs based on a quadruple cation(RbCsMAFA)perovskite.We also compare this derivative with two novel fullerenes decorated with two(EPF01)or one dodecyl(EPF02)long side chains.The latter two fail to perform efficiently in inverted PSCs whereas the former enabled a power conversion efficiency of 18.43%,which represents a 9%improvement compared to the reference device using PCBM(17.21%).The enhanced performance mainly stems from improved electron extraction and reduced recombination enabled by the insertion of the large relative permittivity amongst other properties of EPF03.Furthermore,our results indicate that triethylene glycol side chains can also passivate perovskite trap states,suppress ion migration and enhance photostability and long-term stability of EPF03 based perovskite solar cells.