The synthetic route and properties of three 2D hybrid organic/inorganic lead iodide perovskite materials are reported. The 2D perovskites were synthesized from the reaction between PbI 2 and the di-cations of 1,4diaminobutane, 1,6-diaminohexane, and 1,8-diaminooctane. The resulting products were [NH 3 (CH 2 ) 4 NH 3 ] PbI 4 (BdAPbI 4 ), [NH 3 (CH 2 ) 6 NH 3 ]PbI 4 (HdAPbI 4 ), and [NH 3 (CH 2 ) 8 NH 3 ]PbI 4 (OdAPbI 4 ). Structural characterization shows that two dimensional perovskite structures were formed with inorganic structural planes separated by organic layers. Absorption spectra show band gaps of 2.37 eV (BdAPbI 4 ), 2.44 eV (HdAPbI 4 ), and 2.55 eV (OdAPbI 4 ). The 2D perovskite materials were investigated as light absorbing materials in solid state solar cells.The best performing material under moist, ambient conditions was BdAPbI 4 (1.08% efficiency), which was comparable to methylammonium Pb(II) iodide (MAPbI 3 ) solar cells (2.1% efficiency) manufactured and studied under analogous conditions. When compared to MAPbI 3 , the 2D materials have larger band gaps and lower photoconductivity, while BdAPbI 4 based solar cells shows a comparable absorbed photon-to-current efficiency as compared to MAPbI 3 based ones. † Electronic supplementary information (ESI) available: Tables S1-S4 including atomic parameters of the structure of the three new materials, Fig. S1 and S2, two 2D structures of butyl 1,4-diammonium lead iodide and octyl 1,8-diammonium lead iodide along the three crystallographic axes. Tables S5-S11 and Fig. S3-S9 describe structural and photochemical characterization. CIF les for the structures are available at the Cambridge Crystallographic Data Center (CCDC) referring to the deposition numbers 1420433 and 1420434 for HdAPbI 4 and OdAPbI 4 , respectively. See

In this work, two Cu(II) complex compounds are designed and synthesized for applications as p-type dopants in solid-state perovskite solar cells (PSCs). Through the characterization of the optical and electrochemical properties, the complex Cu(bpcm) 2 is shown to be eligible for oxidization of the commonly used hole-transport material (HTM) Spiro-OMeTAD. The reason is the electron-withdrawing effect of the chloride groups on the ligands. When the complex was applied as p-type dopant in PSCs containing Spiro-OMeTAD as HTM, an efficiency as high as 18.5% was achieved. This is the first time a Cu(II) pyridine complex has been used as p-type dopant in PSCs.

An organic-inorganic integrated hole transport layer (HTL) composed of the solution-processable nickel phthalocyanine (NiPc) abbreviated NiPc-(OBu) 8 and vanadium(V) oxide (V 2 O 5 ) is successfully incorporated into structured mesoporous perovskite solar cells (PSCs). The optimized PSCs show the highest stabilized power conversion efficiency of up to 16.8% and good stability under dark ambient conditions. These results highlight the potential application of organic-inorganic integrated HTLs in PSCs.

Figure 1. Device structure of solid-state dye-sensitized solar cell (ssDSC) and molecular structures of Spiro-OMeTAD and TeCA.

A new redox couple, [Cu(bpye)2]+/2+, has been synthesized and applied in DSSCs. Overall efficiencies above 9.0% and good photostability were obtained. Excellent electrolyte charge transport, fast regeneration and low recombination are the major reasons for the high efficiencies.