No abstract

The main drawback of the methylammonium lead halide perovskite solar cells is their degradation in ambient atmosphere. To investigate ambient-air-induced cell degradation, spectral dependencies of open-circuit voltage (VOC), fill factor (FF) and the power conversion efficiency (PCE) have been acquired (for the first time reported in literature).Our custom-made measurement system allowed us to perform measurements of the abovementioned entities in situ directly in vacuum during and after thermal deposition of the electrode. We also studied how these parameters in vacuum changed after cell exposure to ambient air for 85 min (50 nm top electrode) and for 180 min (100 nm top Ag electrode). For fresh CH3NH3PbI3–xClx cell (never been in open air) with very high shunt resistance of 3·107 Ω·cm2 (with practically no shorts and therefore FF could be determined mainly by charge carrier recombination processes) we found that FF in vacuum increased along with an increase of the incident photon energy from 0.55 at 760 nm up to 0.82 at 400 nm. Hypothesis considering hot polaron participation in charge carrier photogeneration and recombination processes as well as another competing hypothesis were offered as possible explanations for the observed FF increase.The kinetics of short-circuit photocurrent EQE with a change in pressure was also investigated. It was also shown that perovskite solar cell degradation could be noticeably reduced by increasing the top Ag electrode thickness to at least 100 nm, which could possibly facilitate the usual encapsulation process.

Organometal halide perovskites are promising materials for lowcost, high-efficiency solar cells. The method of perovskite layer deposition and the interfacial layers play an important role in determining the efficiency of perovskite solar cells (PSCs). In the paper, we demonstrate inverted planar perovskite solar cells where perovskite layers are deposited by two-step modified interdiffusion and one-step methods. We also demonstrate how PSC parameters change by doping of charge transport layers (CTL). We used dimethylsupoxide (DMSO) as dopant for the hole transport layer (PEDOT:PSS) but for the electron transport layer [6,6]-phenyl C 61 butyric acid methyl ester (PCBM)) we used N,N-dimethyl-N-octadecyl(3-aminopropyl)trimethoxysilyl chloride (DMOAP).The highest main PSC parameters (PCE, EQE, V OC ) were obtained for cells prepared by the one-step method with fast crystallization and doped CTLs but higher fill factor (FF) and shunt resistance (R sh ) values were obtained for cells prepared by the two-step method with undoped CTLs.

Development of hybrid organic-inorganic perovskite solar cells (PSC) has been one of the hottest research topics since 2013. Within brief literature review, we would like to achieve two objectives. Firstly, we would like to indicate that a whole set of physical properties, such as high change carrier mobility, very low recombination rates, large carrier life time and diffusion length, large absorption coefficients and very weak exciton binding energies, are defining high power conversion efficiency (PCE) of methyl ammonium lead trihalide SC. The second objective is to draw attention to some, in our opinion, important aspects that previously have not been satisfactory addressed in literature. Although degradation of PSC is widely discussed, processes at very first exposure to ambient conditions after deposition of top electrode are uncovered.

No abstract

For production organic bulk heterojunction polymer solar cell one of the best materials is regioregular poly-3-hexylthiophene (P3HT), which is widely used as a donor molecule and a hole transporter, with soluble fullerene derivative (PCBM) as acceptor and electron transporter. The main drawback of this highly efficient blend is its limited spectral range, covering only 350-650 nm spectral interval. So main aim of present work was to extend the spectral range of the cell up to 850 nm by adding second bulk heterojunction layer of complementary absorption spectrum to P3HT:PCBM layer. For this purpose hydroxygallium phthalocyanine (GaOHPc) and PCBM blend was used as additional layer because GaOHPc has strong and wide intermolecular charge transfer (CT) absorption band around 830-850 nm. Thus novel organic bi-layer bulk heterojunction system (GaOHPc:PCBM/P3HT:PCBM) has been built by spin coating technique having high charge carrier photogeneration efficiency in 350-850 nm spectral range. It was found that thermal annealing in vacuum at 100C increases short circuit photocurrent external quantum efficiency (EQE) values more than 2-3 times, and these values reach more than 45% at P3HT absorption band (525 nm) and 25% at GaOHPc band (845 nm) for low light intensities (10 12 photon/(cm 2 *s)).

Organometal hybrid trihalide perovskite solar cells (PSCs) have emerged a new class of optoelectronic devices for various applications. PSCs have demonstrated unprecedented progress in efficiency reaching certified power conversion efficiency 22.1% after only several years of active research. In this paper, we demonstrate inverted planar mixed halide perovskite solar cells where perovskite layers are built by two-step modified interdifussion and one-step methods. We demonstrate how PSC parameters change by doping electron transport layer (ETL). We used N,N-dimethyl-N-octadecyl (3-aminopropyl) trimethoxysilyl chloride (DMOAP) as dopant for ETL [6,6]-phenyl C61butyric acid methyl ester (PCBM). The highest EQE and Vocvalues were obtained for cell prepared by one-step method with fast crystallization and doped ETL but higher fill factor (FF) and shunt resistance (Rshunt) values were obtained for cells prepared by two-step method with undoped ETL.