electrode and limits the implantable resolution [17]. Thus, organic OPV cells are re­

volutionizing the research of PV cells, and it is not very far from now that we shall see

self-powered devices based on these OPV.

20.5 Artificial Sensory Organs and Exquisite Biomedical Devices

Several artificial sensory organs have been developed with significant biomedical ap­

plications based on the NG technology described. The new research on the application of

self-powered technology has seen a shift in focus from traditional sensors to areas like the

stimulation of biological tissues and powering crucial life-saving biomedical devices like

pacemakers. A few of these devices have been described in the following section with

some detail.

20.5.1 Electronic Skin (e-Skin)

In the field of next-generation wearable electronics, the e-skins are expected to play a

prominent role with applications ranging from human-machine interaction to defense

equipment and many more. In 2019, Wang et al. considered an e-skin based on PENG

technology [25]. The device was designed to be of a single electrode and was fabricated by

electrospinning PVDF nanofibers capable of sensing pressure and temperature. During

the electrospinning process, it was ensured that the PVDF films were spontaneously po­

larized. The domains inside the material will be inclined towards the external electric field

(Figure 20.6(a–d)). When the sensor is heated or an external force is exerted, the sponta­

neous polarization within PVDF film changes, resulting in a potential difference [25,26]. To

screen this effect, electrons from the external electrodes shall flow, resulting in the gen­

eration of electronic signals. The versatility of this device lies in the fact that two different

signals due to heat and force can be acquired simultaneously using a single device. The

sensitivity of the e-skin lies in the fact that whenever anything touches it, the skin can feel it.

20.5.2 Wound Healing

Severe injuries or traumas are very much troublesome and affect the patient’s daily ac­

tivities. The wounds must heal faster, and the everyday activities are restored quickly. It

has been realized that applying an electric field at regular intervals can lead to faster

healing of wounds. TENG-based technology can produce low-intensity electrical signals

that can be useful for healing skin wounds. Such a TENG was tested on a rat by wrapping

it around the chest area such that during the breathing process, an electric current would

flow around the dressing electrodes resulting in an electric field (Figure 20.6(e–h)) [27].

Regular monitoring of the rat activity revealed that the produced output voltage reached

a maximum level of 2.2 V. Two days of constant monitoring showed that the wound area

was completely healed. Thorough studies revealed that the discrete electric field gener­

ated by the TENG promoted fibroblast proliferation, migration, and transdifferentiation

that led to the faster healing process. Furthermore, the alternating electric field (rather

than direct current) produced by the TENG was far more capable and successful in

promoting the wound healing process [28].

334

Bioelectronics