Augmenting machine learning for Amharic speech recognition: a paradigm of patient’s lips motion detection

Multimedia Tools and Applications - The method of automatic lip motion recognition is an essential input for visual speech detection. It is a technological approach to demystify people who are hard...     

Bulk-heterojunction photovoltaic devices based on donor–acceptor organic small molecule blends

We present a systematic study on photovoltaic devices that combine an organic small molecule photoactive donor–acceptor bulk heterojunction system with controlled doping of the charge transport layers. The doped transport layers are formed using high vacuum co-evaporation deposition technique (i.e. co-sublimation of matrix and dopant). Solar cell devices have been fabricated based on zinc-phthalocyanine (ZnPc) as donor (D) and fullerene (C₆₀) as electron acceptor (A) with doped charge transport layers. The cells show a short circuit current, I_sc=1.5 mA/cm², an open circuit voltage, V_oc=450 mV, a fill factor, FF=0.5, and a power conversion efficiency, η_e=3.37% under sun (10 mW/cm²) white light illumination. In addition, these bulk-heterojunction photovoltaic devices were characterized under 1 sun (100 mW/cm²) white light illumination showing I_sc=6.3 mA/cm², V_oc=500 mV, and η_e=1.04%. We have observed that the performance of such ‘bulk-heterojunction’ photovoltaic devices is critically dependent on the transport properties of the interpenetrating network D/A system and doped charge transport layers.     

Body-Patchable,Antimicrobial, Encodable TENGs with Ultrathin,Free-Standing,Translucent Chitosan/Alginate/Silver Nanocomposite Multilayers

Harvesting sustainable energy opens new avenues for powering portable electronic devices using triboelectric nanogenerators (TENGs). Synthetic metals and polymers are used to construct most of the TENGs. Hence, ultrathin, free-standing, translucent, and chemically bonded chitosan (CH)- and alginate (AL)-based biopolymeric films are introduced here. These films are fabricated using a low-cost and environmentally friendly layer-by-layer (LbL) self-assembly method and impregnated with AgNO₃ (S) in the final fabrication step (denoted as [(CH/AL)_n:(CHS/AL)₁]_n+1). The LbL-assembled film displays remarkable antimicrobial and triboelectric properties, demonstrating a new type of TENG that is implantable in the body. By varying the number of CH and AL depositions, the dependence of TENG behaviors on thickness is investigated. It is demonstrated that a 0.87-µm-thick [CH/AL]₈ TENG resulted in the highest electrical output performance of 474 V and 36.9 mA m⁻² due to the highest surface potential and the lowest work function of 239.4 mV and 4.2 eV, respectively. A free-standing [(CH/AL)₄₉:(CHS/AL)₁]₅₀ TENG is designed for antimicrobial skin-patchable shape-adaptive nanogenerators, displaying ultrahigh translucency, long-term mechanical stability, and exceptional versatility. It is then attached to the arm to detect external stimuli, and the feasibility of its use as an encodable skin-touch sensor is demonstrated.