Integrated Optical Amplifier–Photodetector on a Wearable Nanocellulose Substrate

Abstract

Moreover, the implementation of a wearable photonic technology directly in contact with clothes would be light-weight, comfortable, noninvasive, implantable, and inherently low cost. It attracts a strong interest for industry in this futuristic field. Indeed, according to International Data Corporation, the important growth of this technology is forecasted to grow up to 213.6 millions in 2020. [8] Nowadays, examples of commercial real-time applications include textile-based displays, [9] photovoltaics [9] or health monitoring. [9] In spite of this significant progress, wearable devices still require reduced footprint, better coupling techniques, and the integration of more complex optic/electrical functionalities to meet the performances already provided by traditional semiconductors integrated on rigid substrates.Taking into account these current limitations, metal halide perovskites(MHPs) is a promising semiconductor for flexible/wearable optoelectronic devices because of the outstanding capabilities to provide light emission, gain generation, and photodetection functionalities of polycrystalline MHPs films grown at low temperature. Indeed, MHPs demonstrated a broad range of excellent electrical and optical properties, such as long diffusion lengths, [10] high absorption cross-section, [11] high quantum yield of emission at room temperature, [12] or tunable bandgap with the composition. [13] MHPbased devices include highly efficient solar cells, [14] optical active devices, [12,13,15,16] and photodetectors. [17,18] The majority of these publications, however, use a rigid substrate to fabricate the device, being a significantly lower amount of works on MHP flexible devices with a single functionality as solar cells, [19,20] optical switch, [21] or lasing. [22] On the other hand, nanocellulose (NC) [23,24] has been probed as an ideal substrate for wearable optoelectronics. [25] This polymer is obtained from the most common biopolymer on Earth, and it consists of rigid nanocrystals that can be easily assembled into films and gel materials.NC is not only an excellent bendable, deformable and stretchable material, [26] but also exhibits very interesting properties for optoelectronics. Its advantages comprise a very high transparency in the visible, [27] tunable chiral nematic order by the surface chemistry, [28] low roughness, and extremely high gas barrier properties. [29] Nevertheless, despite these promising abilities, integration of optoelectronic devices in cellulose has been elusive, being it polyimide or polydimethylsiloxane Flexible optoelectronics has emerged as an outstanding platform to pave the road toward vanguard technology advancements. As compared to conventional rigid substrates, a flexible technology enables mechanical deformation while maintaining stable performance. The advantages include not only the development to novel applications, but also the implementation of a wearable technology directly in contact with a curved surface. Here the monolithic integration of a perovskite-based optical wave...

Materials and Designs for Wearable Photodetectors

“…Apart from polymer, paper, and fiber, there are some other materials used as substrates for wearable PDs such as silicon, mica, etc …”

Mechanisms of Spontaneous and Amplified Spontaneous Emission in CH3NH3PbI3 Perovskite Thin Films Integrated in an Optical Waveguide

“…For this purpose, we investigate the evolution of the PL spectra with the extication fluence of polycrystalline layers of MAPI integrated in polymer planar waveguides. We have already demonstrated that this configuration is an optimal one for ASE, because it provides a long path for the emitted photons and highly confines the optical modes of the photonic structure [11,12]. Here, we establish how the geometrical parameters influence the behavior of the waveguide to minimize the ASE threshold.…”

“…Indeed, from the earliest publications with CH 3 NH 3 PbI 3 (MAPI) polycrystalline thin films [9] MHPs have exhibited exceptional optical-gain performances in the visible and near-infrared wavelength range [10]. Low thresholds (1-10 nJ/cm 2 ) of stimulated emission under pulsed excitation were demonstrated in several publications by incorporating perovskite layers into waveguides [11,12], optical resonators [13][14][15], or by synthetizing this material as microdisks [16][17][18] and nanowires [19,20]. More recently, lasing operation in MAPI films under continuous-wave operation was demonstrated [21][22][23].…”

Flexible Sensors—From Materials to Applications

“…Perovskites can be divided into organic-inorganic halide perovskites following the structure ABX 3 (Figure 7a), where A is an organic cation, B is a metal cation and X is an halide anion, or inorganic only halides [272,273]. In flexible sensors, these materials have been mostly employed as active materials in photodetectors, prevalently in the form of organic-inorganic methilammonium lead bromide/iodide/chloride (CH 3 NH 3 PbX or MAPbX) [18,29,272,[274][275][276][277][278][279][280][281], and inorganic caesium lead bromide (CsPbBr 3 ) [282][283][284][285], or as piezoelectric materials such as PbZr x Ti 1-x O 3 (PZT) on ultrasound sensors [286]. The application and development of these materials for flexible optoelectronic applications has been widely researched due to their optical and electrical properties.…”