Cold hypersensitivity in the hands and feet is associated with erectile dysfunction in young Taiwanese men.

Cold hypersensitivity in the hands and feet (CHHF) is a protective or predisposing factor for many diseases; however, the relationship between CHHF and erectile dysfunction (ED) remains unclear. We aimed to investigate associations between CHHF and ED among young men of Southeast Asian origin. In this cross-sectional study, sexually active Taiwanese men aged 20-40 years were enrolled via an online questionnaire comprising general demographic information, comorbidities, subjective thermal sensations of their hands and feet in the past 6 months, and their erectile function using the International Index of Erectile Function-5 (IIEF-5). Participants who reported cold sensation of hands and feet were classified to have CHHF; those with IIEF-5 score ≤ 21 were considered to have ED. Total 54.2% and 27.9% of participants had ED and CHHF, respectively. Men with CHHF were significantly younger, had lower body mass index and IIEF-5 scores (p < 0.001), and a lower prevalence of diabetes mellitus (p = 0.033) along with higher prevalence of ED, psychiatric disorders, and insomnia (p < 0.001). After adjusting for predisposing factors of ED, CHHF (odds ratio 1.410, 95% confidence interval 1.159-1.714; p = 0.001) remained an independent predictor of ED. Thus, CHHF is independently associated with ED, affecting more than a quarter of young Taiwanese men. Autonomic dysregulation and subclinical endothelial dysfunction may be common pathophysiologies of CHHF and ED.

Heat exposure and chronic kidney disease: a temporal link in a Taiwanese agricultural county.

Heat stress-related kidney injury has drawn public health attention. This study explored the temporal relationships between impaired kidney function and preceding outdoor heat exposure Taiwan. Data of participants collected through a health screening program was used to assess the association between chronic kidney disease (CKD) and average ambient temperature with various time lag structures. A total of 1,243 CKD cases and 38,831 non-CKD participants were included in the study. After adjusting for demographic, socioeconomic, lifestyle factors, and comorbidities, CKD was positively associated with the ambient temperature within 1-9 months. The 9-month average ambient temperature yielded the highest odds ratio of CKD (OR = 1.22; 95% CI = 1.09-1.37). Furthermore, females and farmers were found to be more vulnerable to CKD risk after outdoor heat exposure. These findings suggest that the prevention of heat stress-related kidney injury should consider relevant time frames and focus on vulnerable populations.

Adjuvant Sorafenib for Postoperative Patients with Hepatocellular Carcinoma and Macrovascular Invasion.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality in Taiwan. Some patients with HCC are diagnosed with macrovascular invasion (MVI), which is associated with a poorer prognosis. In Taiwan, sorafenib is the first-line therapy for patients with advanced HCC. However, the efficacy of adjuvant sorafenib therapy remains unclear for the subset of patients with HCC and MVI who are eligible for surgery. Therefore, we investigated the potential benefit of adjuvant sorafenib therapy for patients with HCC and MVI after surgery. Our study showed that the lack of improved PFS or OS of adjuvant sorafenib challenged the therapeutic benefit of postoperative sorafenib. Alcohol consumption and an α-fetoprotein level of ≥400 ng/mL were independent predictors of overall survival (OS); however, adjuvant sorafenib therapy was not a predictor of progression-free survival (PFS) or OS. In conclusion, our study indicated that adjuvant sorafenib therapy did not provide PFS or OS benefits in patients with HCC and MVI.

Chronic Kidney Disease Among Agricultural Workers in Taiwan: A Nationwide Population-Based Study.

Introduction: Chronic kidney disease (CKD) in agricultural communities is a significant public health issue. We aimed to investigate the epidemiology of CKD among Taiwanese farmers and its association with outdoor heat exposure. Methods: A nested case-control study was conducted on participants in the National Adult Health Examination (NAHE) from 2012 to 2018. The farming occupation was identified through National Health Insurance data. The primary outcomes of interest were the development of CKD, defined as a decreased estimated glomerular filtration rate (eGFR) with diagnosis by physicians, and CKD of undetermined etiology (CKDu), defined as CKD excluding common traditional etiologies. We calculated the county-wide average ambient temperature from a climate reanalysis dataset (ERA5-Land). All CKD cases were matched 1:2 to non-CKD participants by age and biological sex. We estimated the odds ratios (ORs) of CKD and CKDu for farmers and changes in mean ambient temperature (°C) before the examination. Results: We identified 844,412 farmers and 3,750,273 nonfarmers. Among 24.9% of farmers and 7.4% of nonfarmers with reduced kidney function, only 1 in 7 received a diagnosis of CKD. The farming occupation was independently predictive of CKDu (OR = 1.09, 95% confidence interval [CI] = 1.001-1.18) but not CKD. Increased ambient temperature (°C) was associated with a higher risk of CKD (OR = 1.023, 95% CI = 1.017-1.029), with particularly strong associations observed among middle-aged participants and diabetics. Conclusions: Taiwanese farmers might have a higher risk of developing CKDu. Outdoor heat exposure is associated with the development of CKD, and middle-aged participants and those with diabetes are more vulnerable than the general population.

Pretravel preparation and factors associated with willingness to seek pretravel consultation among Taiwanese travelers.

BACKGROUND: Although globalization promotes economic development, cross-border infectious disease transmission is still a serious threat to health. Taiwan is geographically close to Southeast and South Asia, but the needs and expectations of Taiwanese travelers with regard to travel medicine are still largely unknown. This study aimed to clarify the pretravel preparations, needs, willingness to seek pretravel consultation, and factors associated with willingness, in order to provide valuable information for improvement of healthcare service. METHODS: Data were collected with anonymous structured questionnaires distributed to 477 visitors who tried to get travel health information from New Southbound Health Center between June and November 2019. A multivariate stepwise logistic regression analysis was applied to identify factors associated with the visitors' willingness to seek pretravel consultation. RESULTS: A total of 304 questionnaires (64%) were collected. Eighty-three percent of the respondents were willing to seek pretravel consultation. A higher level of education (odds ratio 3.6 [95% CI 1.58-8.22]), having a plan to obtain travel medical insurance (2.5 [1.18-5.28]), concern with gastrointestinal diseases (2.0 [1.04-3.94]), concern with mosquito-borne diseases (2.0 [2.07-3.95]), and concern with noncommunicable diseases (2.2 [1.02-4.96]) were independent factors associated with willingness to seek pretravel consultation.: CONCLUSIONS: We found that most of the travelers were willing to seek pretravel consultation. Our study highlighted the need to enhance awareness about travel-related illness among these travelers. Strategies should be tailored according to these findings to help prevent epidemics and improve healthcare service in the future.

Impact of team-based community healthcare on preventable hospitalisation: a population-based cohort study in Taiwan.

OBJECTIVES: The objective of this study was to explore the impact of Taiwan's Family Practice Integrated Care Project (FPICP) on hospitalisation. DESIGN: A population-based cohort study compared the hospitalisation rates for ambulatory care sensitive conditions (ACSCs) among FPICP participating and non-participating patients during 2011-2015. SETTING: The study accessed the FPICP reimbursement database of Taiwan's National Health Insurance (NHI) administration containing all NHI administration-selected patients for FPICP enrolment. PARTICIPANTS: The NHI administration-selected candidates from 2011 to 2015 became FPICP participants if their primary care physicians joined the project, otherwise they became non-participants. INTERVENTIONS: The intervention of interest was enrolment in the FPICP or not. The follow-up time interval for calculating the rate of hospitalisation was the year in which the patient was selected for FPICP enrolment or not. PRIMARY OUTCOME MEASURES: The study's primary outcome measures were hospitalisation rates for ACSC, including asthma/chronic obstructive pulmonary disease (COPD), diabetes or its complications and heart failure. Logistic regression was used to calculate the ORs concerning the influence of FPICP participation on the rate of hospitalisation for ACSC. RESULTS: The enrolled population for data analysis was between 3.94 and 5.34 million from 2011 to 2015. Compared to non-participants, FPICP participants had lower hospitalisation for COPD/asthma (28.6‰-35.9‰ vs 37.9‰-42.3‰) and for diabetes or its complications (10.8‰-14.9‰ vs 12.7‰-18.1‰) but not for congestive heart failure. After adjusting for age, sex and level of comorbidities by logistic regression, participation in the FPICP was associated with lower hospitalisation for COPD/asthma (OR 0.91, 95% CI 0.87 to 0.94 in 2015) and for diabetes or its complications (OR 0.87, 95% CI 0.83 to 0.92 in 2015). CONCLUSION: Participation in the FPICP is an independent protective factor for preventable ACSC hospitalisation. Team-based community healthcare programs such as the FPICP can strengthen primary healthcare capacity.

Simulations of Switchback, Fragmentation and Sunspot Pair in δ-Sunspots during Magnetic Flux Emergence.

Strong flares and coronal mass ejections (CMEs), launched from δ-sunspots, are the most catastrophic energy-releasing events in the solar system. The formations of δ-sunspots and relevant polarity inversion lines (PILs) are crucial for the understanding of flare eruptions and CMEs. In this work, the kink-stable, spot-spot-type δ-sunspots induced by flux emergence are simulated, under different subphotospheric initial conditions of magnetic field strength, radius, twist, and depth. The time evolution of various plasma variables of the δ-sunspots are simulated and compared with the observation data, including magnetic bipolar structures, relevant PILs, and temperature. The simulation results show that magnetic polarities display switchbacks at a certain stage and then split into numerous fragments. The simulated fragmentation phenomenon in some δ-sunspots may provide leads for future observations in the field.

Awareness of, attitude toward, and willingness to participate in pay for performance programs among family physicians: a cross-sectional study.

BACKGROUND: The National Health Insurance Administration of Taiwan has introduced several pay-for-performance programs to improve the quality of healthcare. This study aimed to provide government with evidence-based research findings to help primary care physicians to actively engage in pay-for-performance programs. METHODS: We conducted a questionnaire survey among family physicians with age-stratified sampling from September 2016 to December 2017. The structured questionnaire consisted of items including the basic demographics of the surveyee and their awareness of and attitudes toward the strengths and/or weaknesses of the pay-for-performance programs, as well as their subjective norms, and the willingness to participate in the pay-for-performance programs. Univariate analysis and multivariate logistic regression analysis were performed to compare the differences between family physicians who participate in the pay-for-performance programs versus those who did not. RESULTS: A total of 543 family physicians completed the questionnaire. Among family physicians who participated in the pay-for-performance programs, more had joined the Family Practice Integrated Care Project [Odds ratio (OR): 2.70; 95% Confidence interval (CI): 1.78 ~ 4.09], had a greater awareness of pay-for-performance programs (OR: 2.37; 95% CI: 1.50 ~ 3.83), and a less negative attitude to pay-for-performance programs (OR: 0.50; 95% CI: 0.31 ~ 0.80) after adjusting for age and gender. The major reasons for family physicians who decided to join the pay-for-performance programs included believing the programs help enhance the quality of healthcare (80.8%) and recognizing the benefit of saving health expenditure (63.4%). The causes of unwillingness to join in a pay-for-performance program among non-participants were increased load of administrative works (79.6%) and inadequate understanding of the contents of the pay-for-performance programs (62.9%). CONCLUSIONS: To better motivate family physicians into P4P participation, hosting effective training programs, developing a more transparent formula for assessing financial risk, providing sufficient budget for healthcare quality improvement, and designing a reasonable profit-sharing plan to promote collaboration between different levels of medical institutions are all imperative.

Doses of hepatitis B revaccination needed for the seronegative youths to be seropositive to antibody against hepatitis B surface antigen.

OBJECTIVES: To determine the required hepatitis B vaccine doses for subjects who were seronegative for three hepatitis B seromarkers during their youth who wish to have seroprotective antibodies against the hepatitis B surface antigen (anti-HBs). METHODS: We conducted a retrospective cohort study. From 2012 to 2015, graduate school students born after 1986 who were seronegative for three hepatitis B virus seromarkers at college entrance (n = 1037) were recruited. Four groups of subjects received zero to three doses of a hepatitis B vaccine booster at their free willingness, and their anti-HBs titre were measured at their graduate school entrance. Very low and extremely low antibody titres against the hepatitis B surface antigen were elucidated by graphic inference to determine the required booster dose cut-off value for seropositivity after revaccination. RESULTS: The anti-HBs seropositive rates in the four groups of subjects receiving the hepatitis B booster vaccine(s) were 17.7%, 52.1%, 78.6% and 90.9% for those receiving zero, one, two and three doses, respectively. In subjects with very low antibody titres against the hepatitis B surface antigen after one dose of the vaccine booster and subjects with an extremely low titre after two doses of the booster, the seropositive rates reached 95% at the cut-off value of 3 mIU/ml. CONCLUSION: A seropositive rate of at least 95% can be reached by the administration of two hepatitis B booster doses to youths with extremely low antibody titres against the hepatitis B surface antigen (<3 mIU/ml) and administering one dose to those with very low titres (3-10 mIU/ml) at college.

Talc exposure and risk of stomach cancer: Systematic review and meta-analysis of occupational cohort studies.

BACKGROUND/PURPOSE: Talc powder is widely used in various industries, but the carcinogenic effects associated with talc are not well understood. The objective of this study was to estimate the risk of stomach cancer after occupational talc exposure. METHODS: We conducted a meta-analysis was performed to calculate the meta-relative risk (mRR) of stomach cancer. We searched the MEDLINE, EMBASE, CNKI and Wanfang Data databases for publications prior to January 1, 2017 using talc, cancer, and mortality as the search terms. Only cohort studies with occupational talc exposure and stomach cancer statistics were included. RESULTS: All pooled analyses were based on random-effects models. We selected 13 observational studies (12 publications) for the meta-analysis, and heterogeneity was observed among studies. Workers exposed to all forms of talc had a significantly increased mRR of 1.21 (95% CI: 1.03-1.42, p = 0.02) for stomach cancer. Workers exposed to talc not containing asbestiform fibers also had an increased mRR of 1.26 (95% CI: 0.97-1.63, p = 0.09). CONCLUSION: The available data showed a positive association between occupational talc exposure and risk of stomach cancer. The association between talc not containing asbestiform fibers and risk of stomach cancer was not significant. Further epidemiological studies are required to evaluate the safety of talc.

Family physician system in Taiwan.

Following economic development and increasing healthcare demand, Taiwan has not only built a universal healthcare coverage payment system in 1995, but has also developed an accountable family physician system, called the Family Practice Integrated Care Project (FPICP), to deal with the pressures of an ageing society, since 2003. The community healthcare group-based family physician system is not only an important milestone for the development of family medicine in Taiwan but may also even serve as a global example for future family doctor systems. In this review, we aim to review the development of family medicine in Taiwan, the implementation and achievement of the FPICP, as well as the future prospects of system-based healthcare system. We firmly believe that only when the family physician system is well developed and put into practice with person-centered, family as a care unit, and community-oriented holistic care, can the objective of "everyone has their own family doctor" and sustainable operation of National Health Insurance be achieved.

Kinetic study and performance comparison of TiO2-mediated visible-light-responsive photocatalysts for the inactivation of Aspergillus niger.

Fungi are highly survived with exceptional resistance to environmental stress. Conventional fungicides are quite efficient, but the increase in use raises severe environmental problems. In this study, environmentally friendly TiO2-mediated visible-light-responsive photocatalysts, namely N-TiO2, N-T-TiO2, C-TiO2, and Pd-C-TiO2, were used to compare the performance of disinfecting a mold fungi Aspergillus niger. Key parameters, including photocatalyst dosage, the initial fungal concentration, and visible-light intensity, affecting the disinfecting process, was investigated. A new developed Light-responsive Modified Hom's (LMH) kinetic model incorporating visible-light intensity and photocatalyst light-absorption coefficient was firstly used to predict such photocatalytic process in fungal inactivation. Among the photocatalysts, Pd-C-TiO2 showed the highest inactivation performance against fungi, followed by C-TiO2, N-T-TiO2, and N-TiO2. In general, inactivation increased with increasing photocatalyst dosage and light intensity while decreased with increasing initial fungal concentration. For kinetic modeling, the LMH model supports the hypothesis that photocatalyst performance toward visible-light-driven fungal inactivation primarily depends on the light-absorption capacity of the photocatalyst. In conclusion, mold fungi Aspergillus niger are effectively disinfected by TiO2-mediated visible-light-responsive photocatalysts, and such fungal inactivation process could be predicted by LMH kinetic model.

Stomach Cancer and Exposure to Talc Powder without Asbestos via Chinese Herbal Medicine: A Population-Based Cohort Study.

The present investigation was designed to explore the risk of stomach cancer by oral intake of talc powder without asbestos. We conducted a population-based cohort study on a randomly sampled cohort from Taiwan's health insurance database, with population of 1,000,000. The study participants were followed up through 2013. The outcome event of interest was the diagnosis of stomach cancer. The exposure of interest was the prescription of talc powder. Cox regression analyses were performed respectively. There were 584,077 persons without talc exposure and 21,575 talc users, 1849 diagnosed with stomach cancer. Persons with exposure of talc had a higher hazard ratio of stomach cancer (adjusted hazard ratio, 2.13; 95% confidence interval (CI), 1.54⁻2.94; p < 0.001). Classification by cumulative exposure of talc yielded adjusted hazard ratios of stomach cancer of 1.58 (95% CI, 0.79⁻3.17; p = 0.19) and 2.30 (95% CI, 1.48⁻3.57; p < 0.001) among persons with high (>21 g) and medium (6⁻21 g) exposure of talc, as compared to the low-exposure counterparts. Our data demonstrated positive association between increased risk of stomach cancer and oral intake of talc without asbestos. Despite the absence of dose-response effect, there might be a link between stomach cancer and talc.

A Study of Diagnostic Accuracy Using a Chemical Sensor Array and a Machine Learning Technique to Detect Lung Cancer.

Lung cancer is the leading cause of cancer death around the world, and lung cancer screening remains challenging. This study aimed to develop a breath test for the detection of lung cancer using a chemical sensor array and a machine learning technique. We conducted a prospective study to enroll lung cancer cases and non-tumour controls between 2016 and 2018 and analysed alveolar air samples using carbon nanotube sensor arrays. A total of 117 cases and 199 controls were enrolled in the study of which 72 subjects were excluded due to having cancer at another site, benign lung tumours, metastatic lung cancer, carcinoma in situ, minimally invasive adenocarcinoma, received chemotherapy or other diseases. Subjects enrolled in 2016 and 2017 were used for the model derivation and internal validation. The model was externally validated in subjects recruited in 2018. The diagnostic accuracy was assessed using the pathological reports as the reference standard. In the external validation, the areas under the receiver operating characteristic curve (AUCs) were 0.91 (95% CI = 0.79⁻1.00) by linear discriminant analysis and 0.90 (95% CI = 0.80⁻0.99) by the supportive vector machine technique. The combination of the sensor array technique and machine learning can detect lung cancer with high accuracy.

Early Developmental Exposure to General Anesthetic Agents in Primary Neuron Culture Disrupts Synapse Formation via Actions on the mTOR Pathway.

Human epidemiologic studies and laboratory investigations in animal models suggest that exposure to general anesthetic agents (GAs) have harmful effects on brain development. The mechanism underlying this putative iatrogenic condition is not clear and there are currently no accepted strategies for prophylaxis or treatment. Recent evidence suggests that anesthetics might cause persistent deficits in synaptogenesis by disrupting key events in neurodevelopment. Using an in vitro model consisting of dissociated primary cultured mouse neurons, we demonstrate abnormal pre- and post-synaptic marker expression after a clinically-relevant isoflurane anesthesia exposure is conducted during neuron development. We find that pharmacologic inhibition of the mechanistic target of rapamycin (mTOR) pathway can reverse the observed changes. Isoflurane exposure increases expression of phospho-S6, a marker of mTOR pathway activity, in a concentration-dependent fashion and this effect occurs throughout neuronal development. The mTOR 1 complex (mTORC1) and the mTOR 2 complex (mTORC2) branches of the pathway are both activated by isoflurane exposure and this is reversible with branch-specific inhibitors. Upregulation of mTOR is also seen with sevoflurane and propofol exposure, suggesting that this mechanism of developmental anesthetic neurotoxicity may occur with all the commonly used GAs in pediatric practice. We conclude that GAs disrupt the development of neurons during development by activating a well-defined neurodevelopmental disease pathway and that this phenotype can be reversed by pharmacologic inhibition.

Development of breath test for pneumoconiosis: a case-control study.

BACKGROUND: Lipid peroxidation plays an important role in the pathogenesis of pneumoconiosis. Volatile organic compounds (VOCs) generated from lipid peroxidation might be used to detect pneumoconiosis. The objective of this study was to develop a breath test for pneumoconiosis. METHODS: A case-control study was designed. Breath and ambient air were analysed by gas chromatography/mass spectrometry. After blank correction to prevent contamination from ambient air, we used canonical discriminant analysis (CDA) to assess the discrimination accuracy and principal component analysis (PCA) to generate a prediction score. The prediction accuracy was calculated and validated using the International Classification of Radiographs of the Pneumoconiosis criteria combined with an abnormal pulmonary function test as a reference standard. We generated a receiver operator characteristic (ROC) curve and calculated the area under the ROC curve (AUC) to estimate the screening accuracy of the breath test. RESULTS: We enrolled 200 stone workers. After excluding 5 subjects with asthma and 16 subjects who took steroids or nonsteroidal anti-inflammatory drugs, a total of 179 subjects were used in the final analyses, which included 25 cases and 154 controls. By CDA, 88.8% of subjects were correctly discriminated by their exposure status and the presence of pneumoconiosis. After excluding the VOCs of automobile exhaust and cigarette smoking, pentane and C5-C7 methylated alkanes constituted the major VOCs in the breath of persons with pneumoconiosis. Using the prediction score generated from PCA, the ROC-AUC was 0.88 (95% CI = 0.80-0.95), and the mean ROC-AUC of 5-fold cross-validation was 0.90. The breath test had good accuracy for pneumoconiosis diagnosis. CONCLUSION: The analysis of breath VOCs has potential in the screening of pneumoconiosis for its non-invasiveness and high accuracy. We suggest that a multi-centre study is warranted and that all procedures must be standardized before clinical application.

Occupational Exposure to Talc Increases the Risk of Lung Cancer: A Meta-Analysis of Occupational Cohort Studies.

OBJECTIVE: Talc is widely used in industrial applications. Previous meta-analyses of carcinogenic effects associated with inhaled talc included publications before 2004, with a lack of data in China, the largest talc-producing country. The safety of workers exposed to talc was unclear due to limited evidence. The objective of this study was to reevaluate the association between inhaled talc and lung cancer. SETTING PARTICIPANTS AND OUTCOME MEASURES: A meta-analysis was performed to calculate the meta-SMR of lung cancer. We searched the MEDLINE, EMBASE, CNKI, and Wanfang Data databases through March 2017. Data from observational studies were pooled using meta-analysis with random effects models. RESULTS: Fourteen observational cohort studies (13 publications) were located via literature search. The heterogeneity of the included data was high (I-squared = 72.9%). Pooling all the cohorts yielded a meta-SMR of 1.45 (95% CI: 1.22-1.72, p < 0.0001) for lung cancer among the study subjects exposed to talc. Subgroup analysis for asbestos contamination showed no significant difference in lung cancer death between subjects exposed to talc with and without asbestos (p = 0.8680), indicating that this confounding factor may have no significance. CONCLUSIONS: This study provides evidence that nonasbestiform talc might still increase the risk of lung cancer. Further epidemiological studies are required to evaluate the safety of workers with occupational talc exposure.

Diagnostic accuracy of breath tests for pneumoconiosis using an electronic nose.

Breath analyses have attracted substantial attention as screens for occupational environmental lung disease. The objective of this study was to develop breath tests for pneumoconiosis by analysing volatile organic compounds using an electronic nose. A case-control study was designed. We screened 102 subjects from a cohort of stone workers. After excluding three subjects with poorly controlled diabetes mellitus and one subject with asthma, 98 subjects were enrolled, including 34 subjects with pneumoconiosis and 64 healthy controls. We analysed the subjects' breath using an electronic nose with 32 nanocomposite sensors. Data were randomly split into 80% for model building and 20% for validation. Using a linear discriminate analysis, the sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUROC) were 67.9%, 88.0%, 80.8%, and 0.91, respectively, in the training set and 66.7%, 71.4%, 70.0%, and 0.86, respectively, in the test set. In subgroup analysis divided by smoking status, the AUROCs for current smokers, former smokers, and subjects who never smoked were 0.94, 0.93, and 0.99, respectively. In subgroup analysis divided by gender, the AUROCs for males and females were 0.95 and 0.99, respectively. Breath tests may have potential as a screen for pneumoconiosis. A multi-centre study is warranted, and the procedures must be standardized before clinical application.

Use of ultrafast time-resolved spectroscopy to demonstrate the effect of annealing on the performance of P3HT:PCBM solar cells.

The organic solar cells of heterojunction system, ITO/PEDOT:PSS/P3HT:PCBM/Al, with a thermal annealing after deposition of Al exhibit better performance than those with an annealing process before deposition of Al. In this study, ultrafast time-resolved spectroscopy is employed to reveal the underlying mechanism of annealing effects on the performance of P3HT:PCBM solar cell devices. The analyses of all decomposed relaxation processes show that the postannealed devices exhibit an increase in charge transfer, in the number of separated polarons and a reduction in the amount of recombination between excited carriers. Moreover, the longer lifetime for the excited carriers in postannealed devices indicates it is more likely to be dissociated into photocarriers and result in a larger value for photocurrent, which demonstrates the physical mechanism for increased device performance.