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Perovskite solar cells (PSCs) have attracted intensive attention of the researchers and industry due to their high efficiency, low material cost, and simple solution-based fabrication process. Along with the development of device configurations, materials, and fabrication techniques, the efficiency has rapidly increased from the initial 3.8 to recent 22.7%. However, fundamental studies on PSCs are usually yielded through lab-scale procedures and carried out on small-area (≤1 cm) devices. Recently, various deposition methods, such as screen printing, slot-die coating, soft-cover coating, spraying coating, etc., have been developed to enlarge the device area from the millimeters to hundreds of centimeters scale. Herein, we discuss the advances of up-scaling of PSCs and outline the fabrication methods from lab-scale to industrial-scale. Screen printing and slot-die coating have been regarded as the most promising methods toward the mass production of PSCs, and more emerging techniques are also anticipated in this enterprise.

The authors present a study on the evolution behaviors of the transfer characteristics of MoS2 and WSe2 field-effect transistor biosensors when they are subjected to tumor necrosis factor-alpha and streptavidin solutions with varying analyte concentrations. Both MoS2 and WSe2 sensors exhibit very low detection limits (∼60 fM for tumor necrosis factor-alpha detection; ∼70 fM for streptavidin detection). However, WSe2 sensors exhibit the higher linear-regime sensitivities in comparison with MoS2 sensors. In particular, WSe2 sensors exhibit high linear-regime sensitivities up to ∼1.54%/fM for detecting streptavidin at a concentration of ∼70 fM. Such relatively higher sensitivities obtained from WSe2 sensors are attributed to their intrinsic ambipolar transfer characteristics, which make their ON-state carrier concentrations significantly lower than those of MoS2 sensors, and therefore, the target-molecule-induced doping effect results in more prominent channel conductance modulation in WSe2 transistor sensors than in MoS2 sensors. Furthermore, this work strongly implies that the target-molecule-induced surface scattering also plays an important role in determining the response behaviors of the sensors made from atomically layered materials. Especially, the competition between target-molecule-induced p-doping and surface-scattering effects is responsible for the sensor behavior variation observed in the p-type conduction branch of WSe2 sensors. This work advances the critical device physics highly relevant with the fabrication and implementation of reliable nanoelectronic biosensors based on emerging atomically layered semiconductors.