Page 21 - MSAM-3-2

Materials Science in Additive Manufacturing Functional materials for AM

Peltier and Seebeck effects. This feature can be utilized in a Bi Sb Te /epoxy composite. These films created a
0.5
3
1.5
various fields, such as energy harvesting, cooling systems, temperature difference from 4.2 to 7.8 K when the current
and sensors. As the potential difference generated within was between 0.01 and 0.05 A, with a power factor (PF) of
119
a single p-n semiconductor remains at the millivolt scale, 1.12 mW/m·K . This achievement expands the potential
-2
thermoelectric devices achieve higher voltages by linking of the flexible TECs with better cooling performance based
multiple p-n semiconductors in series. For the n-type on the higher PF value. Lu et al. utilized inkjet printing
120
127
component, cationic materials such as TiO and BixSb 2- to fabricate thin film TECs using nanoparticle materials:
2-x
Te , while for the p-type component, anionic materials p-type Sb Bi Te size of 9.8 ±2.7 nm and n-type Bi Te Se
x 3-y 1.5 0.5 3 2 2.7 0.3
such as Ni and Bi (SeyTe ) are used. size of 7.6 ± 1.9 nm on a polyimide (PI) substrate. The
2 1-y 3 -2
The inefficiency in utilizing thermal energy stems maximum PF was approximately 77 μW/m·K at 75°C. This
from the limitation of traditional thermoelectric device finding suggests the potential for improving the drawbacks
manufacturing, which is confined to a 2D plane. Therefore, 3D of conventional nanoparticle thin-film manufacturing
processes, such as complex manufacturing processes and
printing technology, which can overcome these limitations, material wastage. Since thin films are superior in localizing
is gaining attention. There are various thermoelectric cooling and heating compared to bulk devices, they will
128
manufacturing technologies utilizing the 3D printing lead to advancements in fields such as microelectronics
method, including material jetting, vat photopolymerization, and thermochemistry-on-a-chip.
materials extrusion, PBF (SLS), screen printing, dispenser
printing, and inkjet printing. 17,120-124 These techniques offer 3.5.2. Thermoelectric generators (TEGs)
benefits, including the capability to create precise structures,
reduce material wastage, apply diverse materials, and expedite The Seebeck effect is an electrical phenomenon observed
the prototyping process. Recent advances in 3D printing between two semiconductors due to a temperature difference,
119
technology for thermoelectric materials are summarized where electrons migrate from one material to another in
in Table 6, highlighting their improved performance and response to the temperature gradient. TEGs function based
applications in thermoelectric cooler and generator. on the Seebeck effect, and they can generate electricity
from small temperature differences, with the advantages of
3.5.1. Thermoelectric coolers minimal size and lightweight. Therefore, numerous studies
have been conducted to enhance stability and broaden the
Thermoelectric coolers (TECs), which function based on scalability of application areas. A state-of-the-art, flexible
the Peltier effect, offer various advantages. TECs enable TEG with metal chalcogenide nanowires was developed
precise temperature control by directly adjusting power through inkjet printing. The printed films achieved a
through variations in input current. Furthermore, they PF of 493.8 μW/m·K at 400 K and a power density of
-2
have the benefits of low noise and minimized size due to 0.9 μW/m·K using materials such as Ag Te, Cu Te , and
-2
the absence of compressors. Therefore, numerous studies Bi Te Se . This development enhanced both parameters
7
4
2
125
129
have been conducted to enhance stability and increase and demonstrated promising scalability for novel materials.
2.7
0.3
2
cooling efficiency. Moreover, a flexible TEG on a paper substrate was developed
Li et al. fabricated flexible thermoelectric thick through dispenser printing. Materials such as Bi Sb Te and
126
1.5
0.5
3
films using screen printing on a polyimide substrate with Bi Se Te were used, achieving an output power and voltage
2 0.3 2.7
Table 6. Comparison of materials and fabrication methods for thermoelectric
Printing Method Composition Application Performance Reference
Screen Bi0.5Sb1.5Te3/epoxy composite TEC Temperature difference from 4.2 to 7.8 K with current 0.01 126
to 0.05 A, at PF of 1.12 mW/m·K -2
Inkjet p-type Sb Bi Te 3 TEC PF of 77 μW/m·K at 75°C 127
-2
0.5
1.5
n-type Bi Te Se
2 2.7 0.3
Inkjet Ag Te, Cu Te , Bi Te Se 0.3 TEG PF of 493.8 μW/m·K at 400 K and power density of 0.9 129
-2
4
7
2
2
2.7
μW/m·K -2
Dispenser Bi Sb Te , Bi2Se Te 2.7 TEG Output power and voltage of 10 nW and 8.3 mV, 124
3
0.5
1.5
0.3
respectively, with a thousand bending cycles at 35K
Ink dispensing SWCNTs/SDBS, SWCNTs/CTAB TEG PF values of 308 μW/m·K and 258 μW/m·K for the p-type 130
-2
-2
and n-type film, respectively
Abbreviations: PF: Power factor; SWCNTs/CTAB: Single-walled carbon nanotubes/cetyltrimethylammonium bromide; SWCNTs/SDBS: Single-walled
carbon nanotubes/sodium dodecylbenzene sulfonate; TEC: Thermoelectric cooler; TEG: Thermoelectric generator.
Volume 3 Issue 2 (2024) 15 doi: 10.36922/msam.3323