Shorter diffusion length of the electrons than that of the holes is one of the major limitations to boost efficiency of perovskite hybrid solar cells (pero-HSCs). To facilitate electron extraction efficiency in pero-HSCs and make it comparable to that of hole, we, for the first time, demonstrate bulk heterojuncion (BHJ) pero-HSCs fabricated by the mixture of perovskite materials with water/alcohol-soluble fullerene derivatives rather than pristine perovskite materials. Balanced charge carrier extraction efficiency and enlarged interfacial area between perovskite materials and fullerene derivatives are response for enhanced short circuit current densities (J SC ) and enlarged fill factors (FF), consequently, significantly improved power conversion efficiency (PCE) of BHJ pero-HSCs. As compared with planar heterojunction pero-HSCs, more than 22% enhancement in PCE is observed from BHJ pero-HSCs. Remarkable, 86.7% of FF, the highest value for pero-HSCs, is observed from BHJ pero-HSCs. Our strategy of using BHJ structure in pero-HSCs offers an efficient and simple way to further boost the device performance. thin films shown in Figure 9b are inhomogeneous.The inhomogeneous crystal domain observed from CH 3 NH 3 PbI 3 :A 10 C 60 BHJ composite thin films have two different sizes: the one with the domain sizes which are identical to those found in Figure 9a, is probably from CH 3 NH 3 PbI 3 polycrystals; while the other with different domain sizes is probably from A 10 C 60 crystals.The cross-sectional SEM images of ITOBM are displayed in Figures 9e & 9f, respectively. The thickness of each layer is consistent to that in the final devices. Figure 9e shows a PHJ structure of CH 3 NH 3 PbI 3 /PC 61 BM, where the pristine CH 3 NH 3 PbI 3 layer is sandwiched between PEDOT:PSS layer and PC 61 BM ETL. In contrast, in Figure 9f, the CH 3 NH 3 PbI 3 :A 10 C 60 composite layer is sandwiched between PEDOT:PSS layer and PC 61 BM ETL. Moreover, the A 10 C 60 domains can be clearly found in CH 3 NH 3 PbI 3 :A 10 C 60 composite layer. This observation evidently confirms that A 10 C 60 is mixed with CH 3 NH 3 PbI 3 to form CH 3 NH 3 PbI 3 :A 10 C 60 BHJ composite layer.In order to further understand underlying device performance of both PHJ and BHJ pero-HSCs, the investigation of photoluminescence (PL) of BM thin films are conducted. Figure 10a displays the PL spectra of these thin films. It was found that more strikingly PL quenching effect is observed from CH 3 NH 3 PbI 3 :A 10 C 60 BHJ composite thin films than those pristine CH 3 NH 3 PbI 3 thin films, which indeed indicates that efficient electron extraction takes place in H 3 NH 3 PbI 3 :A 10 C 60 BHJ composite thin Graphical Abstract for the table of contents entry in a separate file： ： ： ： Colour graphic: maximum size 8 cm x 4 cm Text: one sentence, of maximum 20 words, highlighting the novelty of the work Bulk heterojunction device structure is invented to address the unbalanced charge carrier extraction efficiencies in perovskite hybrid solar cells. (19 wards)

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We found that 60.0% of confirmed COVID-19 cases occurred in places where the air temperature ranged from 5°C to 15°C. • Our results indicate that SARS-CoV-2 appears to be spreading toward higher latitudes. • The COVID-19 pandemic may spread cyclically and outbreaks may recur in large cities in the mid-latitudes in autumn 2020.

Sensing from ultraviolet-visible to infrared is critical for both scientific and industrial applications. In this work, we demonstrate solution-processed ultrasensitive broad-band photodetectors (PDs) utilizing organolead halide perovskite materials (CH3NH3PbI3) and PbS quantum dots (QDs) as light harvesters. Through passivating the structural defects on the surface of PbS QDs with diminutive molecular-scaled CH3NH3PbI3, both trap states in the bandgap of PbS QDs for charge carrier recombination and the leakage currents occurring at the defect sites are significantly reduced. In addition, CH3NH3PbI3 itself is an excellent light harvester in photovoltaics, which contributes a great photoresponse in the ultraviolet-visible region. Consequently, operated at room temperature, the resultant PDs show a spectral response from 375 nm to 1100 nm, with high responsivities over 300 mA W(-1) and 130 mA W(-1), high detectivities exceeding 10(13) Jones (1 Jones = 1 cm Hz(1/2) W(-1)) and 5 × 10(12) Jones in the visible and near infrared regions, respectively. These device performance parameters are comparable to those from pristine inorganic counterparts. Thus, our results offer a facile and promising route for advancing the performance of broad-band PDs.