Enhanced optoelectronic quality of perovskite thin films with hypophosphorous acid for planar heterojunction solar cells

Solution-processed metal halide perovskite semiconductors, such as CH3NH3PbI3, have exhibited remarkable performance in solar cells, despite having non-negligible density of defect states. A likely candidate is halide vacancies within the perovskite crystals, or the presence of metallic lead, both generated due to the imbalanced I/Pb stoichiometry which could evolve during crystallization. Herein, we show that the addition of hypophosphorous acid (HPA) in the precursor solution can significantly improve the film quality, both electronically and topologically, and enhance the photoluminescence intensity, which leads to more efficient and reproducible photovoltaic devices. We demonstrate that the HPA can reduce the oxidized I2 back into I�, and our results indicate that this facilitates an improved stoichiometry in the perovskite crystal and a reduced density of metallic lead

Enablers for IoT regarding Wearable Medical Devices to Support Healthy Living: The Five Facets

Wearables, body sensor networks, ambient, and Internet of Things (IoT) technologies are currently fairly popular in health-related researches and practices. Definitely, wearable technologies are a central fragment of the IoT. Moreover, wearables are becoming more ubiquitous, and they have noteworthy functions and benefits for healthy living and aging. In this context, the success of wearable medical devices is important. Nevertheless, the current understanding in this field needs enhancements. Hence, the authors conducted a study to identify enablers for IoT regarding wearable medical devices. Explicitly, the authors mainly aimed to identify enablers and relevant characteristics to attain, sustain, and improve success. Consequently, a questionnaire was deployed, and data were collected from 511 participants who are real and current wearable medical device users. For analysis, an exploratory factor analysis methodology was applied. The results show that there are five enablers (dependability; design; worthiness; privacy, confidentiality, and security; compatibility) with 17 items, explaining 75.318% of the total variance. Based on these, the authors crafted a checklist for stakeholders to appraise the relevant devices. This chapter contributes to the pertinent body of knowledge concerning the enablers for IoT regarding wearable medical devices to support healthy living with extracted results. This contribution advances the relevant understanding and is going to be helpful for researchers in the field and wearable medical devices product developers