2D Position-Sensitive Hybrid-Perovskite Detectors

Hybrid organic-inorganic perovskites (HOIPs) have emerged as a versatile class of semiconductors for numerous optoelectronic applications. Here, we demonstrate light-excitation-dependent two-dimensional (2D) position-sensitive detectors (PSDs) using a mixed-phase perovskite, FA_0.83Cs_0.17Pb(I_0.9Br_0.1)₃, as the active semiconductor, incorporated within a five-terminal device geometry. The light-induced lateral photovoltage, which is initiated by selective charge transfer across the metal-perovskite barrier interface, is utilized to achieve the excitation-position-dependent electric response. The 2D PSD devices exhibit a spatially dependent linear variation of the photosignal with sensitivity >50 μV mm^-1 and a low position detection error (1-2%), making them suitable for applications such as quadrant detectors. Further, it is observed that the device architecture plays a key role in controlling the dynamics and linearity of the HOIP PSDs. The large active area devices (up to ∼2 cm × 2 cm) exhibit a distinct spatial variation of the photosignal. We utilize the functionality of the PSD device for light-tracking applications by implementing a continuous detection scheme.

A polymeric bis(di-p-anisylamino)fluorene hole-transport material for stable n-i-p perovskite solar cells

Half-devices made with a norbornene homopolymer with hole-transporting 2,7-bis(di-p-anisylamino)fluorene side chains exhibit improved light and heat stability in comparison to those incorporating spiro-OMeTAD.

Expressions of Prayer in Residential Care Homes

Although the value of spiritual care in the care of older adults is supported by research, few studies have focused specifically on prayer in residential care settings. This ethnographic study with fifteen chaplains and administrators in eleven residential care homes involved analyses of walking interviews and research diaries. Findings revealed the spaces in which prayer happens and the forms it takes. The identities of chaplains-their own spiritual practices, religious beliefs, and positioning within the facility-shaped their dis/comfort with prayer and how they located prayer within public and private spaces. Where organizational leadership endorsed the legitimacy of chaplaincy services, prayer was more likely to be offered. Even in these circumstances, however, religious diversity and questions about secularism left chaplains ambivalent about the appropriateness of prayer. The results demonstrate the relevance of religion and spirituality to residential care, and illustrate how prayer functions as an opportunity for connection and understanding.

Metrology of DNA arrays by super-resolution microscopy

Recent results in the assembly of DNA into structures and arrays with nanoscale features and patterns have opened the possibility of using DNA for sub-10 nm lithographic patterning of semiconductor devices. Super-resolution microscopy is being actively developed for DNA-based imaging and is compatible with inline optical metrology techniques for high volume manufacturing. Here, we combine DNA tile assembly with state-dependent super-resolution microscopy to introduce crystal-PAINT as a novel approach for metrology of DNA arrays. Using this approach, we demonstrate optical imaging and characterization of DNA arrays revealing grain boundaries and the temperature dependence of array quality. For finite arrays, analysis of crystal-PAINT images provides further quantitative information of array properties. This metrology approach enables defect detection and classification and facilitates statistical analysis of self-assembled DNA nanostructures.