Hybrid CPbX 3 (C:C s, CH 3 NH 3 ;X :B r, I) perovskites possess excellent photovoltaic properties but are highly toxic, which hinders their practical application. Unfortunately,a ll Pb-free alternatives based on Sn and Ge are extremely unstable. Although stable and non-toxic C 2 ABX 6 double perovskites based on alternating corner-shared AX 6 and BX 6 octahedra (A = Ag, Cu;B = Bi, Sb) are possible, they have indirect and wide band gaps of over 2eV. However,i si tn ecessary to keep the corner-shared perovskite structure to retain good photovoltaic properties? Here, we demonstrate another family of photovoltaic halides based on edge-shared AX 6 and BX 6 octahedra with the general formula A a B b X x (x = a + 3 b)s uch as Ag 3 BiI 6 ,A g 2 BiI 5 ,A gBiI 4 , AgBi 2 I 7 .A sp erovskites were named after their prototype oxide CaTiO 3 discovered by Lev Perovski, we propose to name these new ABX halidesa sr udorffitesa fter Walter Rüdorff,w ho discoveredt heir prototype oxide NaVO 2 .W es tudied structural and optoelectronic properties of severalh ighly stable and promising Ag-Bi-I photovoltaic rudorffites that feature direct band gaps in the range of 1.79- Photovoltaic (PV) hybrid lead halide perovskites were first reported by Kojimae tal. [1] in 2006 with power conversion efficiency (PCE) of 2.2 %i nadye-sensitized solarc ell (DSSC) device configuration. However,t hese materials gained considerable attention only 6years later after two incremental improvements of their PCE to 3.8 %b yK ojimae tal. [2] and to 6.2 %b yI me tal. [3] Substitution of the liquid electrolyte with an efficient polymer hole-extraction layer by Lee et al. [4] in 2012 increased PCE to 10.9 %and was the turning point in perovskite photovoltaics that openedaway towardh ighly efficient and stable perovskite PV devices.S ince 2012 many researchers, mainly from the dye-sensitized and organic PV fields, joined the exciting research on perovskite solar cells. As ar esult, the PCE of the perovskite solarc ells showed as teep sigmoidal growth thatl ed to the contemporary efficiency of over 22 %. [5] Although this PCE is on par with other highly efficient thin-film PV technologies based on cadmium telluride (CdTe) and copper-indium-gallium selenide (CIGS), lead halide perovskites have the significant advantage of being solution processable, whicho fferss ubstantial cost reduction. Unfortunately,t he relianceo nh ighly toxic Pb hinders the commercial potentialo ft his technology. The toxicity of Pb is very high. The 50 %l ethal dose of lead [LD 50 (Pb)] is less than 5mgp er kg of body weight. In contrast to CdTe, which has excellent stability and negligible solubility in water with as olubility constant of K SP = 10 À34 ,P b-based halide perovskites can easily degrade and Pb can escape from ab roken PV module owing to the moderate solubility of PbI 2 (K SP = 4.4 10 À9 ). Despite various attempts to quantify the impact of potential pollution andi ntroduce life-cycle business modelst hat include integrity monitoring and recycling of perovskite PV modules, ...

In the applications of single-walled carbon nanotubes (SWNTs), it is extremely important to separate semiconducting and metallic SWNTs. Although several methods have been reported for the separation, only low yields have been achieved at great expense. We show a separation method involving a dispersion-centrifugation process in a tetrahydrofuran solution of amine, which makes metallic SWNTs highly concentrated to 87% in a simple way.

Upscaling of perovskite solar cells to module scale and affording long-term stability have been recognized as the most important challenges for commercialization of this emerging photovoltaic technology. In a perovskite solar module (PSM), each interface within the device contributes to the efficiency and stability. Here, we employ a holistic interface stabilization strategy by modifying all the relevant layers and interfaces, namely the perovskite layer, charge transporting layers and the device encapsulation to improve the efficiency and stability of PSMs. The treatments were selected to be compatible with low-temperature scalable processing and the module scribing steps. Our unencapsulated PSM achieved a reverse-scan efficiency of 16.6% with a designated area of 22.4 cm 2 . The encapsulated PSM retained approximately 86% 2 of the initial performance after continuous operation for 2000 h under AM 1.5G light illumination, with translates into a T 90 lifetime of 1570 h and an estimated T 80 lifetime of 2680 h.

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Sn-based perovskite solar cells (PSCs) featuring high performance and long-term stability are very challenging because Sn2+ is relatively prone to oxidation. Here, we have performed coadditive engineering with 5-ammonium valeric acid iodide (5-AVAI) for FASnI3-based perovskite films. From the morphological, structural, and elemental analyses, we observed that 5-AVAI affects the crystal growth of perovskites through its hydrogen bond with I– of the SnI6 4– octahedral. As a result, pinhole-free homogeneous and stable Sn-based perovskite films form over a large area with lower Sn4+ content. This made us able to enhance the power conversion efficiency (PCE) for Sn-based PSCs up to 7% in a 0.25 cm2 aperture area. Most importantly, the 5-AVAI added PSCs showed a record stability and maintained their initial PCE under 1 sun continuous illumination at maximum power point tracking for 100 h.

Single-wall carbon nanotubes (SWCNTs) exhibit resonant absorption localized in specific spectral regions. To expand the light spectrum that can be utilized by SWCNTs, we have encapsulated squarylium dye into SWCNTs and clarified its microscopic structure and photosensitizing function. X-ray diffraction and polarization-resolved optical absorption measurements revealed that the encapsulated dye molecules are located at an off center position inside the tubes and aligned to the nanotube axis. Efficient energy transfer from the encapsulated dye to SWCNTs was clearly observed in the photoluminescence spectra. Enhancement of transient absorption saturation in the S1 state of the semiconducting SWCNTs was detected after the photoexcitation of the encapsulated dye, which indicates that ultrafast (<190 fs) energy transfer occurred from the dye to the SWCNTs.

Large area and stable mixed-cation perovskite solar modules are fabricated via hybrid-CVD, which represents a step forward towards commercialization.