A Study on Zinc Tin Oxide - Based Piezoelectric Nanogenerator

Abstract

Piezoelectric nanogenerator (PENG) are wildly used to fabricated self-powered and wearable electric device, that can extracting random mechanical energy like human movements, solar and wind energy from nature and transformed into electric energy.In order to be able to mass produce and promote a wide range of applications, the selection of sensitive and effective piezoelectric materials and a simple and economical production process are crucial. Here, the simple process to fabricated the PENG that using zinc tin oxide (ZTO) particles were mixed into polydimethylsiloxane (PDMS) without any electrical poling treatment was applied. ZTO has attracted great attention in recent years, due to its high polarization piezoelectricity, controllable shape and size, economical and environmentally friendly. ZTO based PENGs reported mostly used cubes, wires, particles, and belts but without compared the shape influences. In this study, the ethanol precipitation method synthesized product zinc tin hydroxide (ZnSn(OH)₆, ZHS) showing cube and sphere two types using adjusting ratio of NaOH, those products were phase-transformed into amorphous ZTO (ɑ-ZTO) and crystalline ZTO (c-ZTO) after through thermal treatment process. The ZTO nanoparticles uniformly dispersed PDMS mixture was cored on polyethylene terephthalate substrate covered with indium tin oxide (PET/ITO) substrate, that formed ZTO@PDMS film as the responsible for the generation of piezoelectricity of the PENG. The fabricated PENG with cube a-ZTO shows maximum output voltage up to ~4.3V and current ~ 470nA with power of 3.14 µW which is 249% higher than sphere a-ZTO based one, and 255% and 424% greater than cube ZHS and c-ZTO based one, respectively. The various size and shape of ZTO were synthesized through by adjusting the molar ratio of respective materials. The peaks power is shown with 14224.5nm sphere and 11036.5nm cube based PENGs, arrived to ~4.8µW and ~9.94µW, respectively. There are 523% and 727% greater than 100218nm sphere and 82612.8nm sphere based one, respectively. I compared the electrical output with a series of cube and sphere, that dependence same volume. Cube based PENG always shows greater output performance compared to sphere based one, the reason is that the P-E loops shown that the remnant polarization values of cubes-based PENG samples are higher than spheres-based samples. |자가 전원 및 웨어러블 전기 장치를 구현하기 위해, 임의의 기계적 에너지를 전기 에너지로 변환 할 수 있는 압전나노발전기 (PENG)가 널리 사용되고 있다. 본 연구에서는 분극압전성이 우수한 주석아연산화물 (ZTO, zinc tin oxide) 나노 입자를 PDMS (Polydimethylsiloxane)에 혼합하여 전기적 폴링（electrical poling）처리없이 PENG를 제작하였다. 에탄올 침전법 (ethanol precipitation)이용하여 수산화 아연 주석(ZHS, zinc tin hydroxide)을 합성 하였고, NaOH 비율을 조절하여 입방체 (cube)와 구 (sphere) 두 가지 형태로 합성하였다. 이를 후 열처리 공정을 통하여 비정질 (amorphous) ZTO (ɑ-ZTO)와 결정질(crystalline) ZTO (c- ZTO) 로 변경하였다. ZTO 나노 입자가 균일하게 분산 된 PDMS 혼합물을 PET/ITO(polyethylene terephthalate substrate covered with indium tin oxide 기판에 스핀 코팅기법으로 코팅하여 압전발전소자의 활성 층인 ZTO@PDMS 필름(film)을 형성하였다. 큐브(cube) a-ZTO로 제작 된 PENG는 최대 출력 전압 ~ 4.3V 및 전류 ~ 470nA, 3.14µW의 전력을 보였고, 이는 구형 (sphere) a-ZTO 이용한 발전소자 보다 249 % 높았고, 큐브 ZHS 및 큐브 c-ZTO 로 제작한 소자보다 각각 255 % 및 424 % 더 높았다. 다양한 크기의 ZTO를 전구체의 몰비를 조절하여 합성하였다. 피크(peak) 전력은 1400nm 구형 및 1100nm 큐브 이용한 발전소자에서 각각 ~ 4.8µW 및 ~ 9.94µW을 나타냈다. 이 수치는 동일한 부피인1000nm 구형 및 810nm 큐브를 이용한 PENG 보다 각각 523 % 및 727 % 더 높았다. 큐브a-ZTO 이용한 PENG는 항상 구형a-ZTO 이용한 PENG에 비해 더 큰 출력 성능을 나타내었으며, 이는 P-E loop 측정결과를 통해 높은 잔류분극 (remnant polarization)으로부터 기인함을 밝혔다.