Graphene quantum dots (GQDs) are zero-dimensional carbonous materials with exceptional physical and chemical properties such as a tuneable band gap, good conductivity, quantum confinement, and edge effect. The introduction of GQDs in various layers of solar cells (SCs) such as hole transport layer (HTL), electron transport materials (ETM), cathode interlayer (CIL), photoanode materials (PAM), counter electrode (CE), and transparent conducting electrode (TCE) could improve the solar energy (SE) harvesting, separation and transportation of electrons and hole, thus ultimately enhance the overall performance and stability of SCs. The incorporation of GQDs in various layers such as HTL, ETM, CIL, PAM, CE, and TCE achieved photo conversion efficiencies (PCEs) of 18.63, 21.1, 12.81, 9.41, 8.1, and 3.66%, respectively. Furthermore, GQDs improved stabilities such as resistance to degradation for HTL (up to 77%), ETM (80%), resistance to UV light for ETM (94%), resistance to temperature in ETM (90%), and bending stabilities after 1000 cycles for HTL (88%) and for TCE (90%). There are reviews focused on the utilization of different carbon-structured materials such as graphene, carbon nanotubes (CNT), fullerenes, and carbon dots in SCs applications. More specifically, the utilization of GQDs for SCs is limited and yet to be explored in greater detail. This review mainly focuses on the recent advancement of various techniques of production of GQDs synthesis, utilization of GQDs in various layers like HTL, ETM, CIL, PAM, CE, and TCE for the enhancement of PCE, and the stability of SCs. As a result, we believe that an exclusive study on GQDs-sensitized solar cells (GQDSSCs) could provide an in-depth analysis of the recent progress, achievements, and challenges.

In this study, a bipolar visible light responsive photocatalytic fuel cell (PFC) was constructed by loading a Z-scheme g-C3N4/ carbon black/BiOBr and a Ti3C2/ MoS2 Schottky heterojunction on the carbon brush to prepare the photoanode and photocathode, respectively. It greatly improved the electron transfer and achieved efficient degradation of organic pollutants such as antibiotics and dyes simultaneously in two chambers of the PFC system. The Z-scheme g-C3N4/carbon black/BiOBr formed by adding highly conductive carbon black to g-C3N4/BiOBr not only effectively separates the photogenerated carriers, but also simultaneously retains the high reduction of the conduction band of g-C3N4 and the high oxidation of the valence band of BiOBr, improving the photocatalytic performance. The exceptional performance of Ti3C2/ MoS2 Schottky heterojunction originated from the superior electrical conductivity of Ti3C2 MXene, which facilitated the separation of photogenerated electron–hole pairs. Meanwhile, the synergistic effect of the two photoelectrodes further improved the photocatalytic performance of the PFC system, with degradation rates of 90.9% and 99.9% for 50 mg L− 1 tetracycline hydrochloride (TCH) and 50 mg L− 1 rhodamine-B (RhB), respectively, within 180 min. In addition, it was found that the PFC also exhibited excellent pollutant degradation rates under dark conditions (79.7%, TCH and 97.9%, RhB). This novel pollutant degradation system is expected to provide a new idea for efficient degradation of multiple pollutant simultaneously even in the dark.

이산화탄소 배출이 없는 고분자 전해질 막 연료전지(polymer electrolyte membrane fuel cell, PEMFC)는 수송용, 발전용 시스템에 적용 가능한 친환경 에너지 변환장치이다. PEMFC의 주요 구성품 중 하나인 고분자 전해질 막(polymer electrolyte membrane, PEM)은 구동시간 동안의 높은 수소 이온 전도도와 물리화학적 안정성 갖춘 과불소화계 고분자 (perfluorinated sulfonic acid, PFSA) 기반 PEM (PFSA-PEM)이 상용화 되어있다. 하지만 PFSA-PEM의 단점으로 지적되는 낮은 유리전이온도와 높은 기체 투과도의 보완이 요구되고 있다. 이에 본 총설에서는 PFSA-PEM의 성능 향상 및 단점 보완 을 위해 1) PFSA의 측쇄부 길이를 조절함으로써 이온교환용량의 증가와 고분자의 결정성을 증가시켜 PFSA-PEM의 능력을 향상시킨 연구와 2) 유/무기 첨가제를 도입하여 수소 이온 전도도 및 물리적 안정성을 향상시키는 복합 막 연구 및 3) 다공성 지지체를 도입하여 PEM의 두께를 효과적으로 감소시켜 막 저항을 효과적으로 줄이고 내구성을 큰 폭으로 개선한 다공-충진 막에 관한 연구를 소개하고자 한다.

본 연구에서는 다공성 탄소 전극의 음극과 양극 표면에 각각 양이온교환고분자(Nafion)와 음이온교환고분자 (aminated polyphenylene oxide, APPO)를 코팅하여 막 결합형 축전식 탈염(membrane capacitive deionization, MCDI) 공정에 적용하였다. 또한 위 공정의 성능을 탄소 전극만으로 구성한 축전식 탈염(capacitive deionization, CDI) 공정과 비교 평가해 보고 염 제거 효율이 최대로 나타나는 MCDI 공정의 최적 운전 조건을 탐색하고자 하였다. 염 제거 효율은 MCDI 공정이 CDI 공정에 비해 높게 나타났으며 Nafion과 APPO를 적용한 MCDI 공정에서 흡착 조건이 1.2 V, 3 min이고 탈착 조건이 -1.0 V, 1 min 일 때의 염 제거 효율이 82.1%로 최댓값을 보임을 확인했다.

In this study, using a wet chemical process, we evaluate the effectiveness of different solution concentrations in removing layers from a solar cell, which is necessary for recovery of high-purity silicon . A 4-step wet etching process is applied to a 6-inch back surface field(BSF) solar cell. The metal electrode is removed in the first and second steps of the process, and the anti-reflection coating(ARC) is removed in the third step. In the fourth step, high purity silicon is recovered by simultaneously removing the emitter and the BSF layer from the solar cell. It is confirmed by inductively coupled plasma mass spectroscopy(ICP-MS) and secondary ion mass spectroscopy(SIMS) analyses that the effectiveness of layer removal increases with increasing chemical concentrations. The purity of silicon recovered through the process, using the optimal concentration for each process, is analyzed using inductively coupled plasma atomic emission spectroscopy(ICP-AES). In addition, the silicon wafer is recovered through optimum etching conditions for silicon recovery, and the solar cell is remanufactured using this recovered silicon wafer. The efficiency of the remanufactured solar cell is very similar to that of a commercial wafer-based solar cell, and sufficient for use in the PV industry.

Although somatic cell nuclear transfer (SCNT)-derived embryonic stem cells (ESCs) in pigs have great potential, their use is limited because the establishment efficiency of ESCs is extremely low. Accordingly, we tried to develop in-vitro culture system stimulating production of SCNT blastocysts with high performance in the colony formation and formation of colonies derived from SCNT blastocysts for enhancing production efficiency of porcine ESCs. For these, SCNT blastocysts produced in various types of embryo culture medium were cultured in different ESC culture medium and optimal culture medium was determined by comparing colony formation efficiency. As the results, ICM of porcine SCNT blastocysts produced through sequential culture of porcine SCNT embryos in the modified porcine zygote medium (PZM)-5 and the PZM-5F showed the best formation efficiency of colonies in α-MEM-based medium. In conclusion, appropriate combination of the embryo culture medium and ESC culture medium will greatly contribute to successful establishment of ESCs derived from SCNT embryos.

고체 알칼리 연료전지에서는 작동 시 물이 생성되어 water flooding 현상이 나타나는 산화극과 반대로 물이 소진되어 water drying 현상이 나타나는 환원 극과의 water balance 가 매우 중요하다. 이번 연구에서는 기존의 상용막(Fuma tech)을 사용하여 막의 양면에 solvent assisted lithography를 통해 서로 엇갈린 라인 패턴을 형성하였다. 양면 패터닝을 통해 오믹저항의 감소와 함께 water back-diffusion을 향상시켰으며, 넓어진 계면에 의해 산화극의 mass transport를 향상시킬 수 있었다. 또한, 환원극에서는 넓어진 계면에 의해 촉매의 활용률이 증가하였고 이러한 복합적인 효과를 통해, 1.0 Wcm-2 라는 고성능을 얻을 수 있었다.

5-fluorouracil (5-FU) is a pyrimidine analog which can work as antineoplastic antimetabolite by blocking thymidylate synthetase conversion of deoxyuridylic acid to thymidylic acid in DNA synthesis. This study is aimed to know the anticancer effect of 5-FU on the expressions of important signaling proteins in KB cells through immunoprecipitation high performance liquid chromatography (IP-HPLC). KB cells were treated with 5 μM 5-FU and cultured for 12, 24, 48, 72, and 96 hours, and followed by IP-HPLC analysis using 32 antisera. 5-FU suppressed the proliferation of KB cells by decreases in the expressions of proliferation-related proteins, Ki-67, PCNA, CDK4, and MPM2 to 82.6%, 92.4%, 95.2%, and 95.9%, respectively, but increases of antiproliferation-related proteins, p16 and p21 to 106.7% and 125.5%, respectively, during 96 hours of experiment. This proliferation reduction was also negatively regulated by cMyc/MAX/MAD network signaling. The cellular protection and survival were consistently arrested by 5-FU treatment in KB cells. The expressions of NFkB, MDR, p-mTOR, and TNFα were decreased to 95.1%, 92.8%, 93.4%, and 90.3% in 48-72 hours, respectively, while cellular stress was increased by upregulation of p38 to 111.3% in 48 hours. And the expressions of pAKT1/2/3, hTERT, and AMPK were also decreased to 93.3%, 97.4%, and 89.3% in 24-48 hours, respectively, while the cellular transformation might be undergone by upregulation of TGF-β1 to 117% until 96 hours. Particularly, 5-FU treatment greatly induced the cellular apoptosis in KB cells by increased expressions of PARP, cPARP, caspase 9, c-caspase 9, caspase 8, and caspase 3 in the lack of p53/BAX and FASL/FAS signaling. The expressions of PARP and c-PARP were increased maximum to 119.2% in 24 hours, and followed by increases of caspase 9, c-caspase 9, caspase 8, and caspase 3 to 111.2%, 125.9%, 108.6%, and 116.3% in 72-96 hours. Therefore, it is presumed that 5-FU induced cellular apoptosis in KB cells may be derived from the overexpression of PARP due to the increased DNA defect caused by 5-FU, which can lead to ATP depletion and subsequent cellular apoptosis.

표면 플라즈마 처리된 Cu nanoparticle (NPs)로 제작된 Organic photovoltaic (OPV)소자는 일잔 OPV 소자보 다 높은 효율성을 보여준다. Nps는 다양한 합성법으로 제조되어 29 nm의 지름을 가진 입자형태를 갖추었다. 이러한 Nps는 P3HT:PCBM과 결합하여 OPV 활성층으로 사용되었는데 적층방법으로 spin과 bar 코팅 방식을 사용하였다. 제작된 소자의 효율 평가에서 스핀코팅으로 제작된 P3HT:PCBM과 Nps가 결합된 P3HT:PCBM 이 각각 1.01과 4.39%로 Np의 효과로 인한 효율 증가를 볼 수 있었다. 바코팅 프로세스를 (8, 20, 50 um 갭)를 사용하였을 경우 20 um 갭의 바코터에서 스핀코터와 같은 두께의 활성층 두께를 보였다. 제작된 활성층은 바코터 그루브 특성으로 인해 트렌치 패턴이 형성되어 빛 흡수를 약화시켜 효율성을 저하시켰다.