Water-resistant flexible GaN LED on a liquid crystal polymer substrate for implantable biomedical applications

Self-powered flexible inorganic electronic system

“…The entire freestanding ultrathin LSI, composed of a 145 nm thick Si nanomembrane, was transferred from silicon on insulator (SOI) wafer onto a flexible liquid crystal polymer (LCP) and in vivo measurements of biocompatible f-LSI with LCP monolithic encapsulation were performed in live rats. Here, LCP is a promising biocompatible flexible material for implantable in vivo electronic applications given its mechanical stability, chemical resistance, low water absorption, high temperature durability, excellent dielectric property, and low thermal expansion compared to other commercialized flexible substrates such as PET and polyimide (PI) substrate (Table 1) [9]. Moreover, monolithic packaging of LCP can totally block the penetration of ions and moisture while providing small, light, and cost-efficient advantages over conventional biomedical packaging using ceramics and titanium materials [78].…”

“…Many researchers have demonstrated advanced approaches to self-powered flexible inorganic devices, including energy harvesters [1,2], batteries [3,4], high-density memories [5,6], large-scale integration (LSI) [7,8], light-emitting diodes (LEDs) [9,10], and sensors [11][12][13]. In addition, there have been several efforts to realize multifunctional self-powered flexible systems that combine these flexible units on a single plastic substrate [14,15].…”

“…High performance flexible inorganic materials are capable of maintaining their functional properties in warm and humid environments [7,9,16,17]. In light of these aspects, human-integrated therapeutic and monitoring systems can be accomplished by the following approaches, schematically demonstrated in Figure 1.…”

Enhanced emission intensity of vertical aligned flexible ZnO nanowire/p-polymer hybridized LED array by piezo-phototronic effect

“…Therefore, an optimized thickness of the PEDOT:PSS film ($200 nm in our device) is achieved in our experiment to ensure the electroluminescence properties of the device. It is worth mentioning that LED of water-resistance and flexibility has great prospect for applications in biomedicine and moist environment [30][31][32]. Figure S4 shows the water-resistant test of the ZnO nanowire/p-polymer LEDs based on PET substrate.…”

Toward biomaterial-based implantable photonic devices

“…Other examples are implantable LEDs, which have generated interest for biosensing, photothermal and photodynamic therapy, and optogenetics [167][168][169][170]. Of particular interest has been optogenetic applications, which requires integration of miniature light sources deep in the brain to activate specific neurons [169].…”