ABSTRACT
CH3NH3PbI3 has shown great potential for photodetectors and photovoltaic devices due to its excellent positive response to visible light. However, its real-time response characteristics hinder its application in optical memory and logic operation; moreover, the presence of excessive PbI2 is a double-edged sword. Herein, we constructed a dual-terminal device using a single CH3NH3PbI3 micro/nanowire with two Ag electrodes, and then in situ introduced PbI2 quantum dots (QDs) as hole trap centres by thermal decomposition at 160 °C. An anomalous negative photoconductivity (NPC) effect for sub-bandgap light below the PbI2 bandgap is obtained. Importantly, an electrically erasable nonvolatile photomemory can be realized. Furthermore, the device also exhibits an abnormal positive thermal resistance (PTR)-related thermomemory effect, and the thermal-induced high-resistance state (HRS) can be erased by a large bias or an illumination of 365 nm super-bandgap UV light. Additionally, logical "OR" gate operations are achieved through a combination of 650 nm sub-bandgap light and a 70 °C temperature-induced HRS, as well as a large bias and 365 nm super-bandgap light-triggered low-resistance state. These effects are attributed to the excitation and injection of holes in QDs and structural defect traps. This multifunctional device, integrating real-time sensing, nonvolatile memory, and logical operation, holds significant potential for novel electronic and optoelectronic applications.
ABSTRACT
CH3NH3PbI3 is capable of exhibiting a superior photoresponse to visible light, but its self-powered devices are typically formed through p-n junctions. In this study, we fabricated a Ag/CH3NH3PbI3/C dual-terminal asymmetric electrode device using a single CH3NH3PbI3 perovskite micro/nanowire, enabling both the photoresponse and self-powered characteristics of CH3NH3PbI3 to visible light. Compared with traditional p-n junction devices, this simple device demonstrates enhanced interface photovoltaic effects by optimizing the combination of the Ag electrode with CH3NH3PbI3, resulting in superior self-powered characteristics. Under low bias voltage, the device achieves a significant on/off ratio of 103, with superior sensitivity and responsivity as well as a maximum rectification ratio of about 12. The photogenerated voltage and current reach approximately 0.8 V and 2 nA, respectively. This simple, compact, and self-powered asymmetric device exhibits great potential for applications in self-powered optoelectronics and wearable devices. This research provides a promising approach for recognizing and utilizing surface state effects in single nanoscale structures.
ABSTRACT
Objective: Peer support is a concept of substantial significance to health scientists and practitioners today due to its focus shifting from disease treatment to health promotion. Effective incorporation peer relationships in support-enhancing interventions could improve quality care and health outcomes. More and more cases of chronic obstructive pulmonary disease (COPD) have been diagnosed in nonsmokers. In this study, the effects of peer-support nursing intervention on the pulmonary function and quality of life of nonsmoking patients with COPD were investigated. Methods: A total of 100 COPD nonsmoking patients admitted to our hospital from October 2018 to October 2020 were selected as study subjects. All nonsmoking patients were in accordance with the guidelines of COPD diagnosis and treatment issued by the Respiratory Medicine Branch of Chinese Medical Association, and they were not in the habit of smoking. According to the different interventions, the nonsmoking patients were divided into the control group (n = 50) and the observation group (n = 50). Among them, nonsmoking patients in the control group received routine care, and nonsmoking patients in the observation group received routine care and peer-support nursing. The difference on the scores of social support, self-management efficacy, healthy lifestyle, and the distance of six-minute walking were to be compared between the two groups before and after the intervention. Results: There was no significant statistical difference on the general information between the two groups in terms of age, gender, and course of disease (P > 0.05). Before intervention, the social support score involving subjective support, objective support, utilization of support, and total score revealed slight difference between the two groups (P > 0.05). However, after the intervention, the subjective support, utilization of support, and total score remained statistically different between the two groups (P < 0.05), and the objective support showed no significant difference between the two groups (P > 0.05). Before intervention, there was no statistical difference in the self-management efficacy scores such as positive attitude, stress reduction, self-decision-making, and total score between the two groups (P > 0.05). After the intervention, the two groups indicated statistical difference in the self-management efficacy scores (P < 0.05). Before intervention, there was no significant difference between the two groups in the healthy lifestyle score in terms of health responsibility, self-realization, interpersonal support, and stress management (P > 0.05), and the abovementioned outcome measures indicated significant difference between the two groups after intervention (P < 0.05). There was no statistical difference in six-minute walking distance between the two groups before the intervention (P > 0.05), but after the intervention, the observation group revealed a significantly longer distance of six-minute walking compared to the control group (P < 0.05). Conclusion: These data suggest that peer-support nursing intervention can effectively improve pulmonary function and quality of life of nonsmoking patients with COPD.
