Transient electronics (or biodegradable electronics) is an emerging technology whose key characteristic is an ability to dissolve, resorb, or physically disappear in physiological environments in a controlled manner. Potential applications include eco-friendly sensors, temporary biomedical implants, and data-secure hardware. Biodegradable electronics built with water-soluble, biocompatible active and passive materials can provide multifunctional operations for diagnostic and therapeutic purposes, such as monitoring intracranial pressure, identifying neural networks, assisting wound healing process, etc. This review summarizes the up-to-date materials strategies, manufacturing schemes, and device layouts for biodegradable electronics, and the outlook is discussed at the end. It is expected that the translation of these materials and technologies into clinical settings could potentially provide vital tools that are beneficial for human healthcare.

A new type of lead-free halide perovskites is developed and analyzed.

Miniaturized, wearable, and implantable optoelectronic devices and systems provide incomparable opportunities for applications in biomedical fields. Optical filters with wavelength selective reflective/transmissive responses that can be integrated onto these biointegrated platforms are critically important for high performance operation. Here, high quality, dielectric thin‐film optical filters on unconventional substrates via transfer printing are reported. Designed filters formed on flexible substrates exhibit highly spectral selective transmission and reflection, with the maximum optical density at stop band reaching 6. Additionally, freestanding filter membranes are combined with microscale optoelectronic devices, achieving enhanced emission intensity for light‐emitting diodes and spectral sensitivity for photovoltaic detectors. Finally, their in vitro cytotoxicity is evaluated within cell culture, and in vivo biocompatibility is supported in living animals. The presented results offer viable routes to high performance optical components for advanced biointegrated optoelectronic systems.

Biodegradable electronic devices that physically disappear in physiological or environmental solutions are of critical importance for widespread applications in healthcare management and environmental sustainability. The precise modulation of materials and devices dissolution with on-demand operational lifetime, however, remain a key challenge. Silicon nanomembranes (Si NMs) are one of the essential semiconductor components for high-performance biodegradable electronics at the system level. In this work, we discover unusual hydrolysis behaviors of Si NMs that are significantly dependent on the dimensions of devices as well as their surface chemistry statuses. The experiments show a pronounced increase in hydrolysis rates of p-type Si NMs with larger sizes, and mechanical stirring introduces a significant decrease in dissolution rates. The presence of phosphates and potassium ions in solutions, or lower dopant levels of Si NMs will facilitate the degradation of Si NMs and will also lead to a stronger size-dependent effect. Molecular dynamics simulations are performed to reveal ion adsorption mechanisms of Si NMs under different surface charge statuses and confirm our experimental observations. Through geometrical designs, Si NM-based electrode arrays with tunable dissolution lifetime are formed, and their electrochemical properties are analyzed in vitro. These results offer new controlling strategies to modulate the operational time frames of Si NMs through geometrical design and surface chemistry modification and provide crucial fundamental understandings for engineering high-performance biodegradable electronics.

Figure 4. a) Schemes for mechanisms of the light and the ultrasound activated luminescence. Reproduced with permission. [34] Copyright 2020, The Royal Society of Chemistry. b) (Left) Image of a mouse during sono-optogenetic stimulation remotely after injecting ZnS:Ag,Co@ZnS NPs; (right) mechanoluminescence spectra of undoped ZnS (cyan), ZnS:Ag,Co (gray), and ZnS:Ag,Co@ZnS NPs (blue) under focused ultrasound excitation. Reproduced with permission. [35] Copyright 2019, Elsevier. c) (Left) Schematic for chemiluminescence of C-TBD NPs, (middle) fluorescence (FL) and chemiluminescence (CL) images of C-TBD NPs, and (right) FL and CL spectra of C-TBD NPs. Reproduced with permission. [37a] Copyright 2017, Elsevier. d) (Left) Scheme for bioluminescence (BL) with the luciferin-luciferase reaction, and (right) photograph of firefly with BL. Reproduced with permission. [38a] Copyright 2020, Regents of the University of California. e) BL spectra for luciferase in wild-type Macrolampis and the N354E substitution. Reproduced with permission. [38b]