Programmable directional color dynamics using plasmonics

Adaptive multicolor filters have emerged as key components for ensuring color accuracy and resolution in outdoor visual devices.However,the current state of this technology is still in its infancy and largely reliant on liquid crystal devices that require high voltage and bulky structural designs.Here,we present a multicolor nanofilter consisting of multilayered‘active’plasmonic nanocomposites,wherein metallic nanoparticles are embedded within a conductive polymer nanofilm.These nanocomposites are fabricated with a total thickness below 100 nm using a‘lithography-free’method at the wafer level,and they inherently exhibit three prominent optical modes,accompanying scattering phenomena that produce distinct dichroic reflection and transmission colors.Here,a pivotal achievement is that all these colors are electrically manipulated with an applied external voltage of less than 1 V with 3.5 s of switching speed,encompassing the entire visible spectrum.Furthermore,this electrically programmable multicolor function enables the effective and dynamic modulation of the color temperature of white light across the warm-to-cool spectrum(3250 K-6250 K).This transformative capability is exceptionally valuable for enhancing the performance of outdoor optical devices that are independent of factors such as the sun’s elevation and prevailing weather conditions.

Fully implantable and battery-free wireless optoelectronic system for modulable cancer therapy and real-time monitoring

Photodynamic therapy(PDT)is attracting attention as a next-generation cancer treatment that can selectively destroy malignant tissues,exhibit fewer side effects,and lack pain during treatments.Implantable PDT systems have recently been developed to resolve the issues of bulky and expensive conventional PDT systems and to implement continuous and repetitive treatment.Existing implantable PDT systems,however,are not able to perform multiple functions simultaneously,such as modulating light intensity,measuring,and transmitting tumor-related data,resulting in the complexity of cancer treatment.Here,we introduce a flexible and fully implantable wireless optoelectronic system capable of continuous and effective cancer treatment by fusing PDT and hyperthermia and enabling tumor size monitoring in real-time.This system exploits micro inorganic light-emitting diodes(μ-LED)that emit light with a wavelength of 624 nm,designed not to affect surrounding normal tissues by utilizing a fully programmable light intensity ofμ-LED and precisely monitoring the tumor size by Si phototransistor during a long-term implantation(2–3 weeks).The superiority of simultaneous cancer treatment and tumor size monitoring capabilities of our system operated by wireless power and data transmissions with a cell phone was confirmed through in vitro experiments,ray-tracing simulation results,and a tumor xenograft mouse model in vivo.This all-in-one single system for cancer treatment offers opportunities to not only enable effective treatment of tumors located deep in the tissue but also enable precise and continuous monitoring of tumor size in real-time.

Functional photonic structures for external interaction with flexible/ wearable devices

In addition to vital functions,more subsidiary functions are being expected from wearable devices.The wearable technology thus far has achieved the ability to maintain homeostasis by continuously monitoring physiological signals.The quality of life improves if,through further developments of wearable devices to detect,announce,and even control unperceptive or noxious signals from the environment.Soft materials based on photonic engineering can fulfil the abovementioned functions.Due to the flexibility and zero-power operation of such materials,they can be applied to conventional wearables without affecting existing functions.The achievements to freely tailoring a broad range of electromagnetic waves have encouraged the development of wearable systems for independent recognition/manipulation of light,pollution,chemicals,viruses and heat.Herein,the role that photonic engineering on a flexible platform plays in detecting or reacting to environmental changes is reviewed in terms of material selection,structural design,and regulation mechanisms from the ultraviolet to infrared spectral regions.Moreover,issues emerging with the evolution of the wearable technology,such as Joule heating,battery durability,and user privacy,and the potential solution strategies are discussed.This article provides a systematic review of current progress in wearable devices based on photonic structures as well as an overview of possible ubiquitous advances and their applications,providing diachronic perspectives and future outlook on the rapidly growing research field of wearable technology.